ON THIS PAGE:
Causes of Nausea, Vomiting and Appetite Loss
Symptoms
Treatments:
Simple Natural treatments
Anti-Nausea and Anti-Vomiting Medications: Ondansetron (Zofran),
Maropitant (Cerenia)
Acid Blockers:
Famotidine (Pepcid AC), Ranitidine (Zantac 75) and Omeprazole (Prilosec)
Cautions,
Including
Metoclopramide (Reglan)

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Important: Crashing
Alphabetical List of Symptoms and Treatments
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Which Treatments are Essential
Fluid and Urinary Issues (Fluid Retention, Infections, Incontinence,
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Home >
Key Issues
> Appetite
Loss, Nausea and Vomiting
Overview
-
Fortunately, in most cases there are treatments which can help make the
cat feel much more comfortable, but in order to know which treatment would
work best, you need to know the most likely cause in your cat's case.
Causes of
Loss of Appetite, Nausea and Vomiting
Common Causes
Nausea, vomiting and loss of appetite are really common symptoms in CKD cats. Unfortunately, there are a
large number of possible causes, so it can be confusing
trying to decide what might be the cause in your cat's case. To help you
narrow it down, I would scan through the list of symptoms on the
Index
of Symptoms and Treatments page to see if any of them look familiar.
Alternatively, the list below outlines some of the possible causes of nausea,
vomiting and loss of appetite. If you already know that your cat has a
particular problem, say, high phosphorus levels, you can click on the
appropriate link where you will find more information on other symptoms
associated with that condition, which may help you narrow down the cause:
Ask your vet to rule out any of these causes or to treat them if they are
present. Treating any that are present should help stop the vomiting
and appetite loss and make your cat feel more comfortable. In some
cases (e.g. controlling high phosphorus levels), it may also help slow the
progression of the CKD.
Uraemic
Toxins
Even if you rule out or treat the above causes, your cat may still
continue to have problems with vomiting, nausea and appetite loss,
so the chances are you need to read this page even if your cat has some of
the above problems too. Take a look at the list of symptoms
below and see
if they sound familiar — most people find they do.
In such
cases, the problem may be caused by toxins.
As the kidneys gradually lose their ability to regulate
and remove waste products effectively, these waste products build up in
the blood. This is called
uraemia and can make a cat feel very unwell,
because it can affect an area in the brain but outside the blood-brain
barrier called the
central chemoreceptor trigger zone.
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016)
Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I,
Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine &
Surgery 18 pp219-239 mention this.
Although
BUN
is not itself a major toxin, there is a correlation between it and other toxins
which are less easy to measure. Therefore, the higher your cat's BUN or
urea level, the higher the overall toxin load will be, and the more likely it is that s/he
will feel sick and/or vomit.
Feline CKD: Current therapies - what is achievable?
(2013) Korman R & White J Journal of Feline Medicine and Surgery
15(S1) pp29–44 says
"Cats in CKD stages 3-4 often demonstrate gastrointestinal signs of uraemia
(eg, inappetence, nausea, vomiting, stomatitis, gastrointestinal
ulceration, diarrhoea, colitis) and addressing these may improve quality
of life."
Gastric
Hyperacidity (Excess
Stomach Acid)
Gastrin is a gastrointestinal hormone which
stimulates the secretion of gastric acid, which helps the stomach digest
food.
The kidneys are responsible for the excretion of gastrin, but in CKD
this function may not work so well, resulting in the gastrin remaining in
the stomach and potentially stimulating the production of too much gastric
acid.
Feline CKD: Current therapies - what is achievable?
(2013) Korman R & White J Journal of Feline Medicine and Surgery
15(S1) pp29–44 says
"Gastrin is excreted by the kidneys and the concentration increases with
CKD progression, increasing gastric acidity and the risk of ulceration."
This is known as gastric hyperacidity (excess
stomach acid) and can make you feel very unwell. In severe cases stomach ulcers may develop,
which may cause
gastrointestinal bleeding.
It has been widely accepted for many years
that excess stomach acid is a concern for CKD cats, but there is currently some debate as to how big
a role it plays in the symptoms commonly seen in CKD
cats.
Chronic use of maropitant for the management of
vomiting and inappetence in cats with chronic kidney disease: a blinded
placebo-controlled clinical trial (2014) Quimby JM, Brock WT,
Moses K, Bolotin D, Patricelli K Journal of Feline Medicine &
Surgery 17(8) pp692-697 says "Interestingly, the exact mechanism of why CKD cats
suffer from decreased appetite and vomiting is not currently known. Gastrin hormone that is responsible for stomach acid production is
elevated in CKD cats; however, increased stomach acidity and stomach
ulceration have not been document [sic] in humans or cats with CKD. It is
suspected that CKD cats have an increase in toxins referred to as uremic
toxins that trigger the vomiting center (chemoreceptor trigger zone of the
area postrema) in their brains."
Relationship among serum creatinine, serum gastrin,
calcium-phosphorus product, and uremic gastropathy in cats with chronic
kidney disease (2014) McLeland SM,
Lunn KF, Duncan CG, Refsal KR & Quimby JM Journal of Veterinary Internal
Medicine 28(3) pp827-37 compared CKD cats with healthy cats.
They found that 84% of the CKD cats exhibited loss of appetite and 45%
exhibited vomiting, but although the CKD cats did have higher levels of
gastrin compared to the healthy cats, there did not appear to be any
correlation with the severity of the CKD. The study states
"Gastrointestinal signs in these animals may not necessarily be the result
of gastric lesions such as gastric ulceration and inflammation, but
perhaps the consequence of circulating uremic toxins interacting with the
chemoreceptor trigger zone in the brain." It should be noted that the cats
in this study were dead (they were not killed because of the study), so
the measurements taken were post-mortem and therefore did not examine
whether treatments aimed at controlling gastrin levels had any effect.
Evaluation of gastric pH and serum gastrin
concentrations in cats with chronic kidney disease
(2017) Tolbert MK, Olin S, MacLane S,
Gould E, Steiner JM, Vaden S & Price J Journal of Veterinary Internal
Medicine 31(5) pp1414–1419 measured gastric pH in healthy cats
and CKD cats over a maximum period of twelve hours, hypothesising that
cats with excess stomach acid would have lower gastric pH. The study found
that this was not the case and concludes "These findings suggest that cats with CKD may not have gastric
hyperacidity compared to healthy cats and, therefore, may not
need acid suppression. Thus, further studies to determine if
there is a benefit to acid suppression in cats with CKD are
warranted."
Whatever the cause, a CKD cat who exhibits the symptoms listed below needs
help. Generally speaking,
these will be cats with
creatinine
over 3 mg/dl (US) or 265 µmol/L (international) (IRIS stages 3 or 4).
If your cat has relatively low kidney
bloodwork values (creatinine of 2.5-3 mg/dl US, 200-300 µmol/L international)
but nevertheless seems to vomit a lot, it might possibly be because of
CKD-related toxins, but I would also ask your vet to rule out
pancreatitis.
Symptoms
There is no
test as such for toxins, but these are
some of the symptoms you might see (though some of these may also be due
to other causes, as mentioned under each category):
pawing at the mouth
increased drinking
licking gravy only
sitting hunched up
Loss of Appetite
Loss of
appetite is very common in CKD cats and may well be caused by toxins. Human
CKD patients have reported that
their sense of smell and sometimes taste are impaired; this is thought to
be caused by uraemic toxins, and probably occurs in cats too.
There are several other
possible causes of lack of appetite, including
dehydration,
high phosphorus levels, anaemia,
fluid
retention or heart problems,
crashing,
metabolic acidosis,
mouth ulcers, the use
of
antibiotics,
constipation or
hyperthyroidism medication. Dental
problems may also cause appetite loss, as may
pain.
Cats who do
not eat are at risk of developing a potentially life-threatening condition
known as hepatic lipidosis;
Mar Vista Vet
has more information about this. Therefore, it is important to try to find the cause of the
inappetence and
treat it as quickly as possible.
Nausea
Nausea can
be hard to detect, though it often presents as a lack of appetite. The
cat may also lie scrunched up, looking uncomfortable.You may hear the
stomach gurgling. It is perfectly
possible for a cat to have nausea but not to vomit.
High phosphorus levels,
dehydration
or
anaemia may also
cause nausea.
Vomiting
Many CKD cats
vomit regularly without treatment.
Chronic kidney disease (2007)
Polzin D
Delaware Valley Academy of Veterinary Medicine says "vomiting
is reportedly found in one quarter to one third of cats with clinical
signs of uremia."
Vomiting may be seen alone or in conjunction with the other symptoms in
this section.
Sometimes
there may be blood in the vomit - bright red blood is fresh blood, whilst
older blood looks like ground coffee grains. This may be a sign of
mouth ulcers
or of
gastrointestinal bleeding,
but you should contact your vet immediately if you see this symptom - our
George, a non-CKD cat, vomited old blood as the first symptom of severe
liver disease.
Cats who
vomit a lot are more likely to become
dehydrated.
There is a
difference between vomiting and regurgitation. Vomiting is usually
accompanied by a lot of abdominal movement, whereas regurgitation happens
suddenly and with less warning. Vomiting means the cat is emptying the
stomach, whereas regurgitation is where food has not yet reached the
stomach but is being ejected from the oesophagus more or less intact,
often because of eating too fast or hairballs. Regurgitation is often
sausage-shaped.
Veterinary Partner
explains the difference and
has videos showing vomiting versus regurgitation.
Cats who
vomit immediately after eating may have a gastric motility problem -
ranitidine may help with
this, but is now extremely hard to find.
Occasionally vomiting is caused by
constipation,
particularly if your cat vomits before, during or immediately after using the litter tray.
If you are giving your cat sub-Q fluids and s/he regularly vomits after
fluids, this may because of the
type of fluid
used.
Diagnostic and therapeutic approach to common
vomiting in cats (2014) Norsworthy
G Veterinary Medicine is an algorithm to help narrow down the cause
of vomiting in cats.
A practical approach to the common vomiting
patient
(2012) Burrows C Practica Veterinara III 7 pp14-20 discusses
how to narrow down the cause of vomiting.
Washington State University College of Veterinary
Medicine
has information on vomiting.
Coco's page
has practical advice from a CKD parent.
Vet Info has information on vomiting.
Why so many vomiting cats? Getting the diagnosis
(2011) Little S Presentation to the 36th World Small Animal
Veterinary Association World Congress has a flow chart for
narrowing down the cause of the vomiting.
Vomiting cat cases: you can figure them out
(2015) Dr D Zoran NAVC/WVC Proceedings discusses how to
narrow down the cause of vomiting and the possible treatments.
Diagnosis and management of acute and chronic
vomiting in dogs and cats
(2007) Tams TR
Delaware Valley Academy of Veterinary Medicine discusses vomiting.
Pet Place discusses vomiting.
Pet Place
has tips on caring for a vomiting cat.
Vomiting White Foam
Vomiting does not just include food -
the classic symptom in CKD cats is to vomit clear or white foam.
This is often one of the first signs that people notice when their cat is
developing CKD.
Vomiting Water
Sometimes
CKD cats drink a lot on water in one go, then vomit all or most of it up
shortly afterwards. This may be a sign of excess stomach acid. It is possible
that the cat has an urge to drink before vomiting so as to dilute the
stomach acid.
Vomiting in the Morning
CKD cats
often vomit in the morning.
This tends to happen because if a cat goes a long time
without eating (such as overnight), excess stomach acid has more time to
attack the stomach lining and cause vomiting.
Lip Licking
This can be
a sign of nausea and uraemia. It may also be a sign of
dehydration
or possibly pain. Less commonly, it can be a sign of
anaemia. In rare cases it may be caused
by longer term (over three months) use of
metoclopramide
(Reglan).
Teeth Grinding
Cats who
grind their teeth may have uraemia.
Dental
problems
are
another possible cause. It may also be a sign of
dehydration. Very occasionally, this might be a sign of
"rubber
jaw", caused by a condition related to CKD called
secondary hyperparathyroidism.
Animal Dentistry and Oral Surgery
Specialists
discuss the various causes of teeth grinding in cats.
Youtube has a video of a cat grinding his/her teeth.
Hoarseness
CKD cats
may occasionally become rather hoarse because of acid reflux caused by
excess stomach acid.
In some
cases hoarseness may be a sign of
low
potassium levels. Hoarseness is also sometimes seen in cats with
hyperthyroidism. If accompanied by coughing, consider the possibilities of
fluid retention or heart problems.
Drooling (Ptyalism)
Drooling
cats may have problems with
uraemia.
Dental problems or
mouth ulcers may also
cause drooling.
In some cases drooling may be a side effect of using
maropitant (Cerenia).
The Pet Health Network has more
information about drooling.
Pet MD also has some information.
Eating Grass
Cats
commonly eat grass in order to help themselves vomit,
particularly if they want to bring up a hair ball. CKD cats may also eat
grass for this reason, though they may do it because they feel nauseous
generally, and sometimes you feel a little better if you can actually
vomit. It is normally fine to allow your CKD cat to eat grass, as long as
it has not been treated with pesticides.
Yawning and Howling
These may sometimes be symptoms
of uraemia. Howling may have other
causes (see
Index of Symptoms and Treatments).
Hunched over Water Bowl
This can be
a sign of nausea and uraemia. Occasionally it is a sign of
dehydration.
Playing with Water
Some cats
like to play with their water bowls from an early age, but some CKD cats
develop a bit of an obsession with water, and may play with their water
bowl or paw at the water. You may see other new behaviours, such as
drinking from showers or gutters, or hanging around sinks and begging for
fresh running water from the tap. All these types of behaviour may
indicate uraemia. Other possible causes include
dehydration or
diabetes.
Sniffing or Licking or Looking at Food, then
Walking Away
The cat may
approach the food bowl and sniff or lick the food, then walk away. This is a
pretty classic sign of uraemia in a CKD cat, but it may also indicate
mouth ulcers.
Pawing at the Mouth
The most
common reason for this is
dental problems,
but occasionally it is a sign of uraemia.
Increased
Drinking (Polydipsia)
Increased
drinking is common in CKD cats because they usually have problems
maintaining hydration. However, it can also be a symptom of uraemia.
The cat may drink more because, according to
A glass of water immediately increases gastric pH in
healthy subjects (2008) Karamanolis G, Theofanidou
I, Yiasemidou M, Giannoulis E, TriantafyllouK & Ladas SD Digestive
Diseases and Sciences 53(12) pp3128-3132, drinking water may
briefly (only for a few minutes) reduce levels of stomach acid.
In some
cases increased drinking may indicate diabetes.
Licking Gravy Only
The cat may
lick the gravy only and leave any solid food behind. However, this may not
indicate uraemia in all cats, only if it is a new behaviour - my cats
do this all the time and they are healthy, they just prefer pâté-type
foods. Another possible cause is
dental problems.
Sitting Hunched Up
Since cats
with uraemia have sore tummies, they may sit in a hunched up,
uncomfortable position ("meatloafing"). In the worst case, this may indicate
crashing, but only
if you also see the symptoms described there.
Treatments
Although it is not possible to test for toxins,
if your cat is showing any of the
symptoms described
above
(e.g. vomiting white foam),
I would definitely opt to treat. Many people find using
the treatments
outlined below as appropriate (with their vet's approval, of course) helps their cats to
feel noticeably better.
Feline CKD: Current therapies - what is achievable?
(2013) Korman R & White J Journal of Feline Medicine and Surgery
15(S1) pp29–44 says
"Cats in CKD stages 3–4 often
demonstrate gastrointestinal signs of uraemia (eg, inappetence, nausea,
vomiting, stomatitis, gastrointestinal ulceration, diarrhoea, colitis) and
addressing these may improve quality of life."
Although many CKD cats benefit from the treatments described below, the
best treatment depends upon the cause of the problem. For example, many
cats with anaemia lose
their appetites, and the treatments on this page will not help with that,
you need to treat the anaemia. You can check the
Index
of Symptoms and Treatments page for information on treatments for the
other possible causes mentioned above.
People in the USA tend to be routinely offered
treatments for reduced appetite, vomiting or nausea but
this is not always the case in Europe. Although things are slowly improving, it is
still quite possible that if you are in the UK in particular, you will be
offered nothing. In this case, ask your vet to read the
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016)
Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I,
Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine &
Surgery 18 pp219-239, which state "Vomiting
should be actively managed in cats with CKD and nausea should always be
considered as a potential contributory cause in cats with inappetence."
Simple Natural Treatments
I recommend trying these treatments first, because
they need little effort, are inexpensive, are not invasive and can
be tried immediately and without a vet visit (though please inform your
vet if you wish to try slippery elm bark);
yet for some cats they are extremely effective. In fact, for some cats,
especially those in early stage CKD, these may be the only treatments they
need, at least to start with. :
If these treatments are going to help, you would normally see a difference (e.g.
reduced vomiting) within a couple of days. If they are not sufficient, you can talk to your vet about
moving on to using medications, as described further below.
Raising Your Cat's Bowls
Normally a cat
eats with the mouth lower than the stomach, but in CKD cats this can cause
stomach acid to enter the oesophagus and trigger acid reflux. Keeping the
cat's food and water bowls higher than the stomach can help minimise this
problem and may encourage your cat to eat and drink more.
Standing bowls on an upside-down flower pot can often create the correct
height for your cat and provide a sturdy base: choose a flower pot of the
appropriate height for your cat. Some pet stores also sell food dishes on
legs, which are approximately 6 inches (15cm) high.
Classy
Cat Dishes sell raised
stoneware bowls for about US$40. Contrary to what
an Amazon
review says, I have absolutely nothing to do with Classy Cat Dishes, and
definitely do not benefit financially from their sale; I am simply a
satisfied customer of many years standing. The bowls I purchased in 2008 are still in great shape, and my cats love them
(in fact, they refuse to eat from anything else, and become really
indignant if all the bowls are in the dishwasher at the same
time). When I first started using them, I also noticed an
increase in food intake compared to using other bowls. To the left you can see my silly kitten using his Classy Cat dish
in his own inimitable way — he did eventually get the hang of it!
Necoichi
raised bowls are also available from Amazon USA. These are much cheaper
and have good reviews too, though some people think they are too small and/or
too low.
Amazon UK
sells some raised bowls which at least one member of my
support group has used, though I think these would be too deep for some
cats, especially Persians.
The Art of Doing Stuff has ideas on
making your own raised bowls, though I think the ones she uses are too
deep for cats.
Feeding Before Bedtime
You may find that your cat
tends to vomit more during the night or first thing in the morning. This
may be because, if a cat goes a long time without eating, excess
stomach acid has more time to attack the stomach lining. Try to
ensure that your cat eats before bedtime in order to prevent this
—
keeping food constantly in the stomach means the acids are more likely to
attack the food rather than the stomach lining. It may also be worth
setting up an automated feeder on a timer with food in it to keep your cat supplied with food
throughout the night. There are links to such feeders
here.
Slippery Elm Bark
A herbal remedy called slippery elm bark (SEB) is often very
effective for cats with
nausea, vomiting or appetite loss. It soothes the digestive tract, so it can also help with
both constipation
and
diarrhoea.
The
Holistic Treatments page has more detailed information on SEB.
Please inform your vet if you wish to use slippery elm bark.
Nausea and Vomiting Medications:
Ondansetron (Zofran) or Maropitant (Cerenia)
If the natural treatments above don't work, you will
probably have to consider trying additional treatments. Commonly used
medications are:
It is usually safe to use these treatments at the same time as
slippery elm bark or famotidine, but check with your vet first.
Ondansetron and maropitant are usually very effective, particularly for
cats whose CKD is more advanced. They may also be helpful for cats with
additional issues, such as concurrent
pancreatitis or IBD, or
gastric mobility problems. They work in different
ways, so discuss with your vet whether one of them might be suitable for
your cat.
I regularly hear from people whose vets are not familiar with the use of
ondansetron or maropitant in CKD cats and therefore they are
understandably reluctant to prescribe them. In such cases, I would refer
your vet to the
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016)
Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I,
Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine &
Surgery 18 pp219-239, which say "Centrally
acting antiemetics such as maropitant,
mirtazapine, ondansetron and
dolasetron should be considered for management."
Managing pancreatitis and concurrent conditions
(2009)
Robertson J DX Consult 2(1) offers a brief overview of these
treatments.
Ondansetron (Zofran)
Ondansetron is commonly used to control vomiting in cats with pancreatitis
or cancer, but many people find it effective for nausea in CKD cats too.
Ondansetron was first approved for human use in 1990, so it has been
around for a long time. I first heard of somebody using it for a CKD cat in 2002, but it
was not used routinely in CKD cats until recently, mainly because it
was extremely expensive. Since the generic version became available in the
USA, however, it is becoming steadily more
popular for use in CKD cats. Trade names include Zofran in the USA, Setronon in Europe and Emeset in the
UK.
Ondansetron works by selectively inhibiting serotonin 5HT3 receptors,
which is a different mechanism to
metoclopramide (a
medication that was previously used by some people, but which is no longer
commonly prescribed) so it does not lower the
seizure threshold as metoclopramide does.
Pet Place
has some information about ondansetron.
Ondansetron Formulations
Ondansetron Pills
Ondansetron comes in 4mg pills, and a commonly used
dose is 1 mg each time, so one pill contains four doses. The pills are tiny, so can be hard to cut
into quarters.
USA
You can be charged as much as US$6 for a single pill, so you need to shop
around because it is possible to buy the generic pills for a lot less. You may be able to obtain them even more cheaply with a pet medication card (see
Obtaining Supplies Cheaply).
Good RX
Allows you to search for discounted medications in your
area in the USA. As an example, I found 30 ondansetron 4mg for less than US$14 in
NYC.
Honeybee Health
40 tablets (4mg) for $4 or US$9 for 90 (8mg) with free
shipping, but does not ship to all
states.
Costco
30 tablets (4mg) from US$17.55, depending upon the manufacturer and your
location (I searched for NYC).
Health Warehouse
30 tablets (4mg) for US$20.10, but the first order can take up to
two weeks.
Thriving Pets
One tablet (4mg) for US$1, or 60 cents each if you buy 60. A prescription is required.
See
Supplies for shipping
information and a 10% tanya discount code.
UK
Many UK chemists can supply ondansetron with a prescription from your vet.
It is usually much cheaper to buy more pills at one time.
In 2017 there was a shortage of generic ondansetron in the UK. It is now
available again, but you may need to search for it, and prices have risen
massively.
Lloyds Pharmacy
Sells ondansetron for Ł1.66 per tablet with free delivery (minimum order
value
Ł7). A prescription is required.
Viovet
Sell ondansetron, but since it is a human medication, your first
order has to be made over the phone (tel. 01582 842096) and a prescription
supplied. It costs around Ł85 for 30 4mg tablets.
Ondansetron Injectable
There is also an injectable form of ondansetron.
The bottle may say it is for intravenous use, but many
people give injectable ondansetron subcutaneously with no problems. In
fact,
Oral, subcutaneous and intravenous pharmacokinetics
of ondansetron in healthy cats (2014) Quimby JM, Lake RC,
Hansen RJ, Lunghofer PJ & Gustafson DL Journal of Veterinary
Pharmacology and Therapeutics 37(4) pp348–353
found that subcutaneous administration was more effective than oral
dosing.
Unfortunately injectable ondansetron stings a lot, but it may be a good
choice for a cat who is struggling to keep anything down, and it does work
quickly — you should see results within a couple of hours. If you are
giving sub-Qs, it can help if you give some before you give the ondansetron.
Allivet
Sells a
40mg/20ml vial (forty doses for many cats) for US$8.99 per vial.
Thriving Pets
Sells a
30 ml vial in a 1mg/ml strength (thirty doses for many cats) for
US$49.95. See
Supplies for shipping
information and a 10% tanya discount code.
Walgreens
Sells ondansetron injectable in a20ml vial in a 2mg/ml strength for around
US$8. You may be able to use the
Goodrx card.
Costco Canada
sells injectable ondansetron, though no prices are given.
Ondansetron Transdermal
Colorado State University College of Veterinary Medicine looked at the use
of transdermal ondansetron in cats.
Assessment of absorption of transdermal ondansetron
in normal research cats (2017) Zajic LB, Herndon
AK, Sieberg LG, Caress AL, Morgan PK, Hansen RJ, Wittenburg LA, Gustafson
DL & Quimby JM Journal of Feline Medicine and Surgery 19(12) pp1245-1248
found that "transdermal application of 4mg ondansetron does not result in
clinically relevant serum concentrations of drug."
Ondansetron Dosage Amount
A commonly used dose on Tanya's
Support Group is 1 mg each time it is given,
so one pill contains four doses. This ties in with
Pet Place, which mentions that the usual dose
for cats is 0.11mg per pound bodyweight, i.e. 1.1mg for a
10 lb (4.5kg) cat, given 2-3 times a day.
Plumb's Veterinary Drug Handbook mentions an empiric dose of 0.5mg per kg
bodyweight twice daily, so a 10 lb (4.5kg) cat would be given 2.25mg, so a
higher dose.
Ondansetron Dosage Frequency
It used to be the case that twice daily administration was recommended.
This is what Plumb's recommends.
However, twice a day may not be sufficient for many cats.
Oral, subcutaneous and intravenous pharmacokinetics
of ondansetron in healthy cats (2014) Quimby JM, Lake RC,
Hansen RJ, Lunghofer PJ & Gustafson DL Journal of Veterinary
Pharmacology and Therapeutics 37(4) pp348–353
states that "twice daily administration at 0.5 mg/kg is likely inadequate
to maintain serum concentrations within the therapeutic range; higher or
more frequent doses may be needed." It further states that "the
postulated therapeutic range - extrapolated from a previously published
pharmacodynamic study - may not be accurate particularly if applied to
repeated administration for chronic disease states."
Pet Place mentions that the usual dose
for cats is 0.11mg per pound bodyweight every 8-12 hours, i.e. 1.1mg for a
10 lb (4.5kg) cat given 2-3 times a day.
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016)
Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I,
Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine &
Surgery 18 pp219-239 recommend a dosage of
0.5–1.0 mg/kg given subcutaneously every 6–8 hours, so a 10 lb
(4.5kg) cat would receive 2.25- 4.5mg subcutaneously three or four
times a day.
The problem is that cats seem to vary widely in their ability to utilise
ondansetron.
Oral, subcutaneous and intravenous pharmacokinetics
of ondansetron in healthy cats (2014) Quimby JM, Lake RC,
Hansen RJ, Lunghofer PJ & Gustafson DL Journal of Veterinary
Pharmacology and Therapeutics 37(4) pp348–353
says that "Poor bioavailability should be taken into
account when determining a route of administration for a patient as
individual oral bioavailability ranged from 11 to 50% in the cats used in
this study." You may therefore need to experiment to find the optimum dose
and frequency for your cat.
For acute vomiting, such as in a cat with pancreatitis, higher dosing may
be necessary. For chronic nausea in CKD cats, however, many people find a dose
of 1mg is fine, but needed at least twice daily, and if that doesn't work,
then three times daily. Very occasionally, cats need ondansetron four
times a day.
I would start with a dose of 1 mg twice a day, and if you find this
is not enough, speak to your vet about increasing the frequency initially,
and if necessary, the dose.
Ondansetron Side Effects and Interactions
Possible side effects include constipation, low blood pressure and sleepiness. Humans have reported bad
headaches.
Drugs has more information about possible
side effects.
It was previously reported that when given intravenously to humans in high
doses, ondansetron may cause heart arrhythmias. In June 2012
The US Food & Drug Administration
reported that "a 32 mg single intravenous dose of ondansetron
(Zofran, ondansetron hydrochloride, and generics) may affect the
electrical activity of the heart (QT interval prolongation), which could
pre-dispose patients to develop an abnormal and potentially fatal heart
rhythm known as Torsades de Pointes." Ondansetron
and the risk of cardiac arrhythmias: a systematic review and postmarketing
analysis (2014) Freedman SB,
Uleryk E, Rumantir M & Finkelstein Y Annals of Emergency Medicine 64(1)
pp19-25 looked into this and concluded "No reports describing an
arrhythmia associated with single oral ondansetron dose administration
were identified." For those apparently affected by intravenous ondansetron
"A significant medical history (67%) or concomitant use of a QT-prolonging
medication (67%) was identified in 83% of reports. Approximately one third
occurred in patients receiving chemotherapeutic agents, many of which are
known to prolong the QT interval. An additional third involved
administration to prevent postoperative vomiting." This is probably not a
concern for most CKD cats, but discuss with your vet if you are worried.
There is some debate as to whether ondansetron causes
serotonin syndrome.
The US Food and Drug Administration
states that it may, though it says that "The majority of reports of
serotonin syndrome related to 5-HT3 receptor antagonist use occurred in a
post-anesthesia care unit or an infusion center." It also says that
serotonin syndrome is more common when given at the same time as
medications such as
mirtazapine (used in CKD cats as an appetite stimulant).
Drugs also mentions that using ondansetron and
mirtazapine together may
increase the risk. However,
Can 5-HT3 antagonists really contribute to serotonin
toxicity? A call for clarity and pharmacological law and order
(2014) Rojas-Fernandez CH Drugs - Real World Outcomes 1(1)
pp 3–5 disputes that ondansetron causes serotonin syndrome. Discuss with
your vet whether to give both medications, and if you do so, give them at
least two hours apart.
Ondansetron inhibits the analgesic effects of
tramadol: a possible 5-HT3 spinal receptot involvement in acute pain
in humans (2002) Arcioni R,
della Rocca M, Romano S, Romano R, Pietropaoli P & Gasparetto A
Anesthesia and Analgesia 94(6) pp1553-7 reports that
ondansetron may reduce the painkilling effects of
tramadol by up to 50% in humans. It is not known if the same applies
to cats.
Dolasetron
(Anzemet)
I occasionally hear from people who are using another
drug in the family as ondansetron, dolasetron (Anzemet). The main advantage of
dolasetron is that it only needs to be given once a day, but for some
reason it is not used often in CKD cats and seems to be more commonly used for cats with pancreatitis.
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016)
Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I,
Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine &
Surgery 18 pp219-239 mention a dose of
1.0 mg/kg once a day given subcutaneously, so
a 10 lb (4.5kg) cat would receive 4.5mg each day subcutaneously.
However,
Preliminary pharmacokinetics of intravenous and
subcutaneous dolasetron and pharmacodynamics of subcutaneous dolasetron in
healthy cats (2018) Herndon
AK, Quimby JM, Sieberg LG, Davis L, Caress AL,
Ligas S, Hansen RJ, Wittenburg LA & Gustafson DL Journal of Feline Medicine
and Surgery 20(8) pp721-727 found that a dose of 0.8 mg/kg
given intravenously or subcutaneously did not last for 24 hours in the
body and did not appear to prevent vomiting in healthy cats. A higher dose
of 1mg/kg also did not prevent vomiting. The study concludes that further
research is necessary to determine the efficacy and optimal dose for cats.
Plumb's Veterinary Drug Handbook mentions that dolasetron should not be
given to patients with certain types of heart problem, and should be used
with caution in cats with
low potassium levels.
Pharmacologic control of vomiting
(2009) Tams TR CVC in Kansas City Proceedings has some
information about dolasetron.
Maropitant
(Cerenia)
Maropitant (Cerenia)
is a relatively new treatment which works by inhibiting neurokinin
(NK) inhibitors. In other words, it works by blocking the stimulation of
the part of the brain that instigates vomiting.
Maropitant: novel antiemetic
(2015) Trepanier LA Clinician's Brief Feb 2015 pp75-77
explains more about how it works.
The injectable form is approved for the treatment of vomiting and nausea
in cats (and dogs) in Europe and the USA. In Europe, injectable maropitant
is also approved for travel sickness in cats.
Treatment for visceral pain with the new NNK-1
receptor antagonist maropitant in cats
(2011) Boscan P, Monnet E, Twedt D & Nyiom S, found that maropitant
may also be an effective painkiller, so it may be a good choice for a
vomiting cat with
pancreatitis.
Maropitant only needs to be given once a day and does appear to be very
effective for some cats, usually (though not always) taking effect within
an hour. Chronic
use of maropitant for the management of vomiting and inappetence in cats
with chronic kidney disease: a blinded placebo-controlled clinical trial
(2015) Quimby JM, Brock WT, Moses K, Bolotin D, Patricelli K Journal of
Feline Medicine & Surgery 17(8) pp692-697 found that there was
a significant reduction in vomiting in CKD cats given maropitant; however,
it did not seem to improve appetite.
Maropitant use in cats (2020) Quimby JM
Today's Veterinary Practice May/Jun 20 has an overview of
maropitant use in cats
Some people find maropitant works better for their cats than ondansetron,
so if you are not finding ondansetron as effective as you hoped,
even though you are dosing optimally, you may wish to talk to your vet
about trying maropitant instead.
Maropitant Formulations
Maropitant is available in either injectable or pill form. Both are intended to prevent vomiting, but the
injectable form is also designed to treat acute vomiting. Only the
injectable form is approved for use in cats, but the pill form is used off
label.
The injectable form seems to sting some cats.
Prevomax is an injectable form of
maropitant that was introduced in the UK and Europe in early 2018. It
contains a preservative that is supposed to reduce the pain of injection.
The oral form seems to taste horrible.
Maropitant Tablets
Maropitant comes in 16mg-sized tablets so most people use these and break
them into suitable sizes for their cat. Make sure you are not given larger size tablets intended for humans.
USA
Valley Vet
Sells four 16mg tablets for US$15.05 with free shipping for orders over
US$60 (shipping costs US$7). I have used Valley Vet myself in the past for
other products with no problems.
KV Supply
Sells four 16mg tablets for US$15.44.
Chewy
Sells four 16mg tablets for US$16.72.
Allivet
Sells four 16mg tablets for US$16.72.
UK
Viovet
Sells four 16mg tablets for Ł10.99.
Canada
Universal Pet Meds
sells four 16 mg size tablets for CAN$9.97.
Pets Drug Mart
sells 16 mg size tablets for CAN$2.68 each.
Maropitant Injectable
Unfortunately there is no generic injectable form of maropitant, and
injectable Cerenia is expensive. A typical dose
would be 4mg daily (0.4 ml), so a 20 ml vial of a 10mg/ml concentration provides 50 doses. You may be able to get maropitant more cheaply from a
compounding pharmacy.
Injectable maropitant stings very badly, though keeping it in the fridge
may help with this. The new version called
Prevomax which was introduced in
the UK and Europe in early 2018 contains a preservative that is supposed
to reduce the pain of injection.
Once opened, the vial should be stored in the fridge anyway.
Drugs states that it will keep for 90
days in the fridge, but that the stopper should not be punctured more than
25 times, so whether you can really get 50 doses from your vial is
debatable.
USA
Thriving Pets
Sells a 20ml vial of 10 mg/ml strength for US$219.95. This provides around 50 doses
(depending upon the size of the cat), so each dose would cost US$4.40. A prescription
is required. See
Supplies for shipping
information and a 10% tanya discount code.
UK
Prevomax is available in a 20ml vial of 10 mg/ml size.
Vetimed
Sells one vial for Ł102.71. This provides around 50 doses (depending upon
the size of the cat), so each dose would cost just over Ł2. A prescription is required. I do not know
anyone who has used this company as yet (April 2020).
Canada
Universal Pet Meds
Sell a 20ml vial of 10 mg/ml for CAN$179. This provides around 50 doses
(depending upon the size of the cat), so each dose would cost just over
CAN$3.50.
Maropitant Dosages
Maropitant Oral
Safety, pharmacokinetics and use of the novel NK-1
receptor antagonist maropitant (Cerenia) for the prevention of emesis and
motion sickness in cats (2008)
Hickman MA,
Cox SR,
Mahabir S,
Miskell C,
Lin J,
Bunger A,
McCall RB Journal of Veterinary
Pharmacology and Therapeutics 31(3) pp220-9 states "The results
indicate that maropitant is an effective, well tolerated and safe
anti-emetic in cats at a dose of 1.0 mg/kg."
The manufacturer recommends this dose, as do Plumb's Veterinary Drug
Handbook and
Pet Place.
A 10 lb cat (4.5 kg)
cat would therefore receive 4.5 mg a day, or a quarter of a 16mg tablet.
However, some cats need up to double this dose, i.e. 2mg per kg (2.2lbs) a day,
or 9 mg a day (half a 16mg tablet a day) for a 10lb (4.5kg) cat.
Many vets seem concerned that 2mg/kg might be too high a dose, but it is
recommended by
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016) Sparkes AH,
Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C,
Lefebvre H, White J & Quimby J Journal of Feline Medicine and Surgery
18 pp219-239, which state "2 mg/kg q24h [once a day]." I
have heard from a few people who think this dose may have caused some
lethargy in their cats but I have not heard of any other issues.
Oral maropitant is famous for tasting horrible, even if you try to use a
flavoured variety. Many people place the medication in a
gelatine
capsule in order to hide the taste. Unfortunately the pills should not be given in
Pill
Pockets or mixed with food as this may stop them being properly
absorbed in the cat's body, but some people do give them this way and
still find them effective.
The European Medicines Agency
states that halved tablets should be stored in the foil they came
in and that the shelf life of halved tablets is only two days. I have not
yet heard from anybody who throws away the last half or quarter of their
tablets, but if you think your cat's response to maropitant seems to be
inconsistent (e.g. your cat vomits every fourth day), this might explain
why.
Maropitant Injectable
The
European Medicines Agency
states that the injectable form is given
-
"once daily under the skin (1ml per 10 kg bodyweight) for up to five
days"
-
the injectable form comes in a 10mg/ml strength, so 1ml contans 10mg
-
Therefore a 10 lb (4.5kg) cat would receive 4.5mg a day, or 0.45 ml.
Plumb's Veterinary Drug Handbook states that
-
0.5 to 1 mg per kg bodyweight can be given for up to five days.
-
Therefore a 10 lb (4.5kg) cat would receive 2.25-5.00 mg a day,
or 0.225-0.5ml a day.
As with the oral medication, some cats do fine on the lower dose, whilst
others require the higher dose. I have heard from a few people who think
this dose may have caused some lethargy in their cats but I have not heard
of any other issues.
Safety, pharmacokinetics and use of the novel NK-1
receptor antagonist maropitant (Cerenia) for the prevention of emesis and
motion sickness in cats (2008)
Hickman MA,
Cox SR,
Mahabir S,
Miskell C,
Lin J,
Bunger A,
McCall RB Journal of Veterinary
Pharmacology and Therapeutics 31(3) pp220-9 states "Safety of
maropitant was determined following 15 days of subcutaneous (SC)
administration at 0.5-5 mg/kg. Maropitant was well tolerated in cats at
doses that exceeded the efficacious anti-emetic dose range of the drug by
at least a factor of 10."
The injectable form seems to sting some cats (unless you are using
Prevomax), though keeping it in the fridge before use, and injecting it
into the fluids lump after giving sub-Qs may make it sting less.
Maropitant Dosing Frequency
One of the main problems with maropitant is the issue of whether you
should have regular breaks when giving it.
The manufacturer used to recommend that maropitant should only be given
short term to dogs, for a maximum of five days at a time.
Off label use of drugs in veterinary medicine
(2013) Coates J explains that using maropitant for longer can
reduce dopamine levels in the central nervous system and lead to tremors.
In 2015, the
manufacturer announced that the FDA had
approved a change in the labelling of maropitant in tablet form to allow
for it to be given once daily to dogs over the age of seven months until
the vomiting is resolved. The recommendation for dogs aged between two and
seven months remained at a maximum of five days at a time.
In the manufacturer's study into the use of injectable maropitant in cats,
the maropitant was only given for five days. As far as I am aware, the
manufacturer has not assessed maropitant when given daily to cats for
longer periods, whether injectable or in tablet form. Therefore most
people giving maropitant to their cats used to err on the side of caution
and would give maropitant for up to five days, take a break, then use it
again. Plumb's Veterinary Drug Handbook mentions that the medication
should be stopped for at least 48 hours in these circumstances.
In
Safety, pharmacokinetics and use of the novel NK-1
receptor antagonist maropitant (Cerenia) for the prevention of emesis and
motion sickness in cats (2008)
Hickman MA,
Cox SR,
Mahabir S,
Miskell C,
Lin J,
Bunger A,
McCall RB Journal of Veterinary
Pharmacology and Therapeutics 31(3) pp220-9, maropitant was
used for fifteen days without a break in cats with no apparent problems,
though one cat did have minor tremors while asleep. I know that after
learning about this study, some people have given their cats maropitant
for longer than five days and not seen any adverse effects.
In a more recent study,
Chronic use of maropitant for the management of
vomiting and inappetence in cats with chronic kidney disease: a blinded
placebo-controlled clinical trial (2015) Quimby JM, Brock WT,
Moses K, Bolotin D, Patricelli K Journal of Feline Medicine and
Surgery 17(8) pp692-7, 4 mg of maropitant was given orally to
cats once every day for 14 days without a break. Colorado State University
College of Veterinary Medicine, which led this study, has stated that it
is prepared to give its patients maropitant on a daily basis without a
break.
Veterinary Partner explains more about
maropitant's
mechanism. It says "Originally, a five
days on/one day off schedule was recommended for long-term use but, now that maropitant has been out for many years,
long-term use has come to be more common without skipping days."
Some members of Tanya's CKD Support Group do give maropitant without a
break. Others use it but do take a break and use
ondansetron on break days.
Be guided by your vet on the best approach for your cat, and monitor your
cat closely for tremors or shaking.
Maropitant Side Effects and Interactions
Possible side effects include vomiting, lethargy, diarrhoea, anorexia,
twitching and drooling. Maropitant should not be used if there is
any gastrointestinal obstruction, and should be used with caution if liver
or heart problems are present (it may increase the risk of arrhythmias).
Drugs has
more information.
The European Medicines Agency
says "Since maropitant could affect heart activity, Cerenia should
be used with caution in animals with certain heart conditions." I do not
know which heart conditions this is referring to, but check with your vet
if your cat has any kind of heart condition.
The European Medicines Agency also says
(clause 4.8 on page 9) that "Cerenia should not be used concomitantly with
Ca-channel antagonists as maropitant has affinity to Ca-channels." In
principle this means that maropitant should not be used with calcium
channel blockers such as
amlodipine (Norvasc or Istin, commonly used to treat high blood
pressure in CKD cats).
'Concomitantly' has a rather vague medical meaning in that it
means during the same time period, but in this context I don't know
exactly what time period the EMA is referring to, i.e. do they mean at the
same time or on the same day? Both of these medications tend to be given
once daily, so they have a relatively long effect. I suspect that giving
them both on the same day but 12 hours apart (i.e. one in the morning and
one in the evening) would probably be acceptable, and indeed one member of
Tanya's CKD Support Group reported in 2020 that her cat vomited if she
gave maropitant and amlodipine close together, but there was no vomiting
if they were given 12 hours apart. Discuss the best approach for your cat
with your vet.
The European Medicines Agency
also warns that urgent medical attention should be sought if
maropitant gets in the eyes.
Cerenia information sheet (tablets)
states that maropitant may interact with phenobarbital, used to control
epilepsy, and
NSAIDs.
Cerenia information sheet (injectable)
also mentions this.
Acid Blockers
There are two main classes of acid blocker
used in CKD cats:
Until relatively recently, it was routinely
recommended that CKD cats should be given acid blockers, and usually as
the first step in a treatment plan for vomiting and nausea.
11 guidelines for conservatively treating chronic
kidney disease (2007) Polzin D,
Veterinary Medicine December 2007
say "H2 blockers are most commonly used, and few adverse effects have
been attributed to their use. Antiemetics are typically added when
anorexia, nausea, or vomiting persist despite the use of an H2 blocker."
However, recently there has been some debate as to whether CKD cats actually suffer
from excess stomach acid which needs controlling (see
above), so these medications have fallen rather out of favour.
However, they do seem to help many CKD cats,
and
whilst other treatments may be helpful, as discussed above, many people
still use acid blockers, not only because they find them helpful, but also
because they are cheap and easily available over the counter in most
countries (though please do not use any of these treatments without your
vet's approval).
proton pump inhibitors
Histamine H2 Antagonists
Histamine H2 antagonists
block the production of stomach acid rather than neutralise it.
Famotidine (Pepcid
AC),
ranitidine
(Zantac 75) and
cimetidine
(Tagamet)
all belong to this category of medications.
Because histamine H2 antagonists are long-acting, they have long
been considered a good choice
for treating stomach acid problems.
Current concepts for the management of chronic renal
failure in the dog and cat - early diagnosis and supportive care
(2005) Sanderson S Presentation to the 30th World Congress of the World Small
Animal Veterinary Association states that it is
generally recommended to use such treatments in CKD cats once creatinine is over 3
mg/dl (USA) or 265 mmol/L
(international).
That is quite an old paper and recently there has been a lot of debate in scientific circles as
to how effective the histamine H2 antagonists are in CKD cats.
This is largely because of a study,
Evaluation of gastric pH and serum gastrin
concentrations in cats with chronic kidney disease
(2017) Tolbert MK, Olin S, MacLane S,
Gould E, Steiner JM, Vaden S & Price J Journal of Veterinary Internal
Medicine 31(5) pp1414–1419, which measured gastric pH in healthy cats
and CKD cats over a maximum period of twelve hours, hypothesising that
cats with excess stomach acid would have lower gastric pH. The study found
that this was not the case and concludes "These findings suggest that cats with CKD may not have gastric
hyperacidity compared to healthy cats and, therefore, may not
need acid suppression. Thus, further studies to determine if
there is a benefit to acid suppression in cats with CKD are
warranted."
Because of this study, I am hearing from people whose vets are
now reluctant to prescribe histamine H2 antagonists, even if
they have used them before. I think this response is premature,
and may be caused by some statements made in the study, e.g. it
states "Chronic administration of acid suppressants has been
associated with calcium and PTH derangements, osteoporosis, and
pathologic fractures in at risk human populations."
That statement refers to humans, not to cats. In addition, this
study looked at only ten CKD cats, 50% of whom were in IRIS
Stage 2, so below the level where these medications
are normally used. Even the study itself does not advise
against giving them, saying "additional
studies are warranted both to evaluate gastric pH in cats with
later stages of CKD as well as to determine if there is an
actual benefit of acid suppression in cats with CKD."
ACVIM consensus statement: support for
rational administration of gastrointestinal protectants to dogs
and cats (2018) Marks SL, Kook PH, Papich MG, Tolbert
MK & Willard MD Journal of Veterinary Internal Medicine
32(6) pp1823-1840 states "Critical assessment of acid
suppressants in experimental models and dogs and cats with
spontaneous disease is sparse, and most of the studies
evaluating the efficacy of acid suppressants were performed in
healthy animals." Or, as in the 2014 McLeland study cited
above, deceased. The
consensus statement concludes "Renal disease: No evidence for acid suppressant therapy in
animals with IRIS 1-3 CKD. More data is needed for animals in
IRIS stage 4."
Famotidine (Pepcid AC)
Famotidine (Pepcid
AC) has long been a popular treatment in the USA for feline
CKD cats, though less so in recent times as the medications discussed
above become
more popular. It seems to be an effective
treatment, though there are very few studies into
the use of famotidine in cats, particularly CKD cats, and recent studies
are questioning its effectiveness. One such study,
Evaluation of the effect of orally administered acid
suppressants on intragastric pH in cats (2015) Parkinson S, Tolbert K, Messenger K, Odunayo
A, Brand M, Davidson G, Peters E, Reed A & Papich MG Journal of
Veterinary Internal Medicine 29(1) pp104-112, states "These
results suggest that both omeprazole formulations provide superior acid
suppression in cats compared to famotidine or placebo" but this small
study was conducted in healthy cats. Many people do report that famotidine
does seem to help their cat feel better.
As a side effect, famotidine may reduce
parathyroid hormone levels in CKD patients.
Famotidine reduces serum parathyroid hormone levels
in uremic patients (1991) Arik N, Arinsoy T,
Sayín M,
Taşdemir I,
Yasavul U,
Turgan C,
Caglar S Nephron 59(2) p333
explains more about this. I would not use famotidine to treat elevated PTH
levels only.
Pet Place has more information
about famotidine.
Famotidine Formulations
Famotidine is available as a generic or, in the USA, under the brand name Pepcid AC. Famotidine may be sold under a
different name in your country (e.g. Amfamox, Famox or Pepcidine in New Zealand and
Australia).
General Medical shows which trade names
famotidine is known by in various countries.
Famotidine is available in the USA as a tablet, oral suspension or as an
injectable.
It has recently been found that elderly human patients with Covid-19
appeared to have a better chance of survival if they were taking
famotidine, with the result that many pharmacies have currently sold out.
Famotidine Tablets
USA
Pepcid AC (Regular Strength) in the USA contains 10mg
of famotidine. If you opt for the brand name, there are
quite a few Pepcid products available so make sure you buy the correct one. You need Pepcid
AC 10mg but not the chewable type, and not Pepcid Complete, both of which have some ingredients which make them unsuitable for
CKD
cats. There is also a new version called Pepcid Maximum Strength, which is
the same as Pepcid AC except that it contains twice as much famotidine, so
be very sure you have the correct strength (10mg tablets).
Using generic famotidine is acceptable, but make sure it is
the correct strength and that it does not contain any additional
ingredients.
Walmart
Sells 90 10mg tablets under its own Equate brand for US$7.88
UK
Pepcid AC has been discontinued in the UK and
replaced by PepcidTwo. PepcidTwo contains magnesium and calcium in
addition to famotidine, so it is not suitable for CKD cats.
Famotidine does exist in generic form and is available from chemists, but
only in 20mg size, which could be difficult to cut into cat-sized doses; plus it requires a
prescription from your vet.
If you really want
to use famotidine, it is sometimes available from
Amazon UK in the 10mg strength at prices
ranging from Ł5-65 (search for Pepcid AC or famotidine), though I couldn't
find any when I checked in April 2020.
It has recently been found that elderly human
patients with Covid-19 appeared to have a better chance of survival if
they were taking famotidine, with the result that many pharmacies have
currently sold out.
Target
in the USA sells 30 famotidine 10mg tablets for Ł2.89
for 30 tablets plus shipping and taxes. Minimum order is US$25.
Summit Veterinary
Pharmaceuticals
Sells famotidine in compounded cat-sized tablet form in a 5mg size (so
you only need to cut the pills in half) but your vet has to order it for
you. 100 tablets cost around Ł16 plus VAT (2018) and your vet's mark up.
The Specials Laboratory
Sells famotidine in compounded cat-sized form, though they do actually
offer 2.5mg capsules. Ninety 2.5mg capsules cost Ł93.79, or 100 5mg tablets
for Ł46.20, both plus VAT and shipping costs of around Ł12.50. They also
sell
100ml of
famotidine 2.5mg per ml for Ł91.89, with a 90 day expiry from manufacture.
These prices were as at 2018.
Bova UK/
A veterinary specials manufacturer that sells chicken flavour 5mg tablets. These can only be ordered by
your vet.
Famotidine Oral Suspension
Famotidine is also available as an oral suspension (liquid) in the USA. It
is widely available from compounding pharmacies, and usually costs around
US$20 for a month's supply.
Famotidine Injectable
Some people prefer to use this because famotidine tastes very bitter in
pill or oral suspension form. You
can use the injectable either by injecting it directly into your cat, or
if your cat is on sub-Qs, by adding it to the injection port of your IV
line.
There are two types of famotidine injectable. There is a 10mg/ml
strength without preservative, which is available in 2ml vials. Because it
contains no preservatives, this has a short shelf life (it is intended for
single use in humans). There is also a 10mg/ml strength available in
a 20ml
size vial. This contains a preservative and can be re-used, though it
needs to be shipped chilled and should be kept in the fridge after you
receive it. It is safe to take it out of the fridge about 30 minutes before using it so it can
warm up a little before use.
Injectable famotidine is often out of stock so you may have to search for
it.
Thriving Pets
Sell the 10mg/ml
injectable form of famotidine in a 20ml size for US$19.95 in the USA. If you want to give the
usual famotidine dose of 2.5mg, you would give 0.25ml, thus the 20ml size
contains 80 doses altogether. See
Supplies for shipping
information and a 10% tanya discount code.
Westmont Pharmacy
Sells the
10mg/ml form. A box of 25
bottles of 2ml (50 ml total) costs US$40.
Famotidine
Dosage
Famotidine is excreted by the kidneys, and cats with CKD cannot process it
as efficiently as healthy cats, so it may
accumulate in the cat's body and cause problems.
Drug
dose adjustments for disease (2010) Trepanier LA CVC in Washington Proceedings discusses
the need to adjust dosing levels for some medications when diseases
including CKD are present.
Below are suggestions for famotidine dosages for CKD cats, but be guided by
your vet. You should only use famotidine with your
vet's approval. Do not start with the maximum dose, it could be risky.
Starting dose: |
2.5 mg once every other day
i.e. quarter of a 10mg tablet once every two days e.g. on Mon, Wed, etc. |
Intermediate dose (if starting
dose does not seem to be helping):
|
2.5mg once
a day i.e.
quarter of a 10mg tablet once a day |
Maximum dose: |
2.5mg twice a day
i.e. quarter of a 10mg tablet twice a day, 5mg a day in total |
If you are only giving famotidine once a day, I would recommend doing so at bedtime because
this seems to help cats who vomit at night or first thing in the morning. Famotidine tastes quite bitter and can make cats foam at the mouth, so you may find it easier to give it in a
gelatine
capsule (gelcap) or to use the injectable form (see
above). It usually takes effect
pretty quickly, within a couple of days for most cats.
Some people find that after a while, famotidine seems to be less
effective. Evaluating the prolonged use of an antacid,
famotidine, in cats is a study
funded by the Winn Feline Foundation in 2017 which investigated if it
does become ineffective in cats and whether changing the dose might help.
Evaluating the effect of prolonged famotidine
administration in cats (2018) is
the final report on the study which concluded that famotidine does become
less effective over time but that this can be avoided if given every other
day rather than daily.
Famotidine Side Effects and Interactions
The most common side effects in humans are constipation or diarrhoea.
Although famotidine can be purchased
over the counter, please do NOT give it without first discussing it
with your vet, particularly if your cat has advanced CKD, because it is
excreted by the kidneys so may not be appropriate.
Some cats, particularly those with high bloodwork
(creatinine over 5 mg/dl (USA) or 450 µmol/L (international)),
do not seem to do well on famotidine, perhaps because their kidneys cannot excrete
it efficiently as described above. These cats may in fact exhibit increased vomiting
and appetite loss when given it - this happened to our
Thomas.
Drugs
mentions how an overdose may cause vomiting. If your cat's vomiting
and appetite loss do not improve after two days of using famotidine,
ask your vet about switching to another treatment.
Famotidine may adversely affect cats with existing heart rhythm problems.
Veterinary Partner
has more information on famotidine, and mentions how it may adversely
affect cats with such problems.
Medicine Net mentions that famotidine may cause
anaemia in humans.
This does not appear to be a problem in cats given oral famotidine, but
there are rare reports of intravenous famotidine causing haemolytic
anaemia in cats.
Risk of hemolytic anemia with intravenous
administration of famotidine to hospitalized cats
(2008) de Brito Galvao JF & Trepanier LA Journal
of Veterinary Internal Medicine 22(2) pp325-9 found that
"the IV route appeared safe when famotidine was administered over 5
minutes."
Web MD
reports that human CKD patients on famotidine may exhibit abnormal levels
of drowsiness.
Chronic kidney disease (CKD) in dogs and cats - staging and management
strategies (2015) Chew D
Presentation to the Virginia Veterinary Medical Association 2015 Virginia
Veterinary Conference states that "Calcium
carbonate binds phosphorous best in an acidic environment (pH approx. 5)
and binding capacity is reduced in the neutral pH range. Many CKD patients
receive inhibitors of gastric acid secretion potentially reducing calcium
carbonates ability to bind phosphorous." I did use calcium-based
binders and famotidine with Ollie with no problems, but if you are using
calcium-based phosphorus binders such as Ipakitine or Pronefra, I would discuss the situation with your vet.
Famotidine can interfere with antibiotics in the
cephalosporin family such as
cefovecin (Convenia), so you should separate the two treatments by two hours.
I am sometimes asked why I mention this when Convenia is an injectable
medication. H2-antagonist cephalosporin interactions
(2003) Ali A Thesis states "These interaction studies with H2-receptor antagonists in
gastric as well as blood pH revealed that simultaneous use of
these drugs depressed the availability of the antibiotic as well
as cimetidine, ranitidine and famotidine." Plumb's
Veterinary Drug Handbook does not mention cefovecin (Convenia)
specifically, but does mention that taking other members of the
cephalosporin family with food may offset the reduced absorption of
the antibiotic.
Famotidine may reduce the absorption of vitamin B12 from
food.
Proton pump inhibitor and histamine H2 receptor
antagonist use and vitamin B12 deficiency
(2013) Lam JR, Schneider JL, Zhao W
& Corley DA Journal of the American Medical Association 310(22)
pp2435-2442 found that in humans "gastric acid inhibitor use was
significantly associated with the presence of vitamin B12 deficiency."
Therefore if you are using famotidine, it might be worth supplementing
vitamin B12.
I used to recommend giving famotidine at least two hours apart from
sucralfate (Carafate
or Antepsin) or
metoclopramide (Reglan), because, according to
Plumb's Veterinary Drug Handbook, these other medications could bind
with the famotidine and thereby reduce its effectiveness. However, the
most recent edition of Plumb's does not mention this requirement, so it
appears that you do not need to separate famotidine from these other
medications after all.
RX Med states that "concomitant use of
aluminum hydroxide/magnesium hydroxide at commonly used doses, does not
influence the pharmacodynamics or bioavailability of Pepcid AC." Plumb's does still recommend separating famotidine from
phosphorus
binders and
ACE inhibitors. I would try to err on the side of caution and still separate
famotidine from phosphorus binders and ACE inhibitors if you can, but if
this is difficult for you, e.g. because of work commitments, just do the
best you can.
Ranitidine (Zantac
75)
Another popular over the counter histamine H2 antagonist is
ranitidine (trade name is Zantac 75), which works in a similar
way to
famotidine. Some people prefer to use ranitidine, especially
if their cat has experienced increased vomiting with famotidine,
as happens with a small number of cats (usually those with
creatinine over 5 mg/dl USA or 450 µmol/L international).
The effect of orally administered
ranitidine and once-daily or twice-daily orally administered
omeprazole on intragastric pH in cats
(2015) Šutalo S, Ruetten M, Hartnack S, Reusch CE & Kook
PH Journal of Veterinary Internal Medicine 29(3)
pp840-6 concluded "standard dosages of ranitidine were not
effective acid suppressants in cats." Nevertheless, I do hear
from people who find ranitidine effective.
Ranitidine helps with gut motility. According to
Feline constipation, obstipation and
megacolon: prevention, diagnosis and treatment (2001)
Washabau R Presentation to the World Small Animal Veterinary
Association World Congress, ranitidine may also help some
cats with
constipation.
Pet Place has more information
about ranitidine.
Ranitidine and Cancer-Causing Ingredient
Ranitidine used to be available in tablet, injectable and oral suspension
form, and was widely available throughout the world. Unfortunately in
September 2019 Zantac was recalled worldwide because it may contain a
carcinogenic (cancer-causing) ingredient called N-nitrosodimethylamin
(NDMA).
The US Food & Drug Administration
explains more about this.
The recall initially applied only to Zantac, not to generic versions of
ranitidine. However, on 1 April 2020 the
US Food & Drug Administration requested
the removal of all ranitidine products from the market with immediate
effect. This means ranitidine will not be available in any form in the
USA, and many other countries are taking the same approach. The FDA
further advises that you should not use any ranitidine which you currently
have in your possession.
The US Food and Drug Adminstration has
some FAQs about the removal, and states that it also applies to compounded
and injectable ranitidine.
Canada takes a different approach to ranitidine.
Health Canada
says "Based primarily on animal studies, NDMA is classified as a
probable human carcinogen. We are all exposed to low levels of NDMA
through a variety of foods (such as smoked and cured meats, dairy products
and vegetables), drinking water and air pollution. NDMA is not expected to
cause harm when ingested at low levels. For example, a person taking a
drug that contains NDMA at or below the acceptable level every day for 70
years is not expected to have an increased risk of cancer."
Health Canada also states "Health Canada permitted companies wishing to
resume sales to do so provided they test every batch of ranitidine product
before releasing it and regularly throughout its shelf life, to
demonstrate that products do not contain higher than accepted levels of
NDMA."
I think the best approach is to discuss the pros and cons of ranitidine
with your vet.
Ranitidine Formulations
Ranitidine Tablets
Ranitidine tablets are available in a 75mg size (though other
sizes also exist).
The
main problem with ranitidine tablets is dividing them into
cat-sized dosages - they usually have to be cut into eighths
(assuming you are using the 75mg size). If you find it hard to
cut the pill into eight, you could try dissolving it in water
and giving an eighth of the resulting mixture via syringe.
UK
In
the UK ranitidine usually costs around Ł1.20 for 12 75 mg
tablets. Many people like to buy the branded product, Zantac 75,
but generic ranitidine is widely available, though be sure to
check the ingredients before using because many of these
products seem to contain additional ingredients, not all of
which may be appropriate for cats.
If
you would prefer not to have to cut the tablets yourself,
Summit
Veterinary Pharmaceuticals
sells ranitidine in compounded cat-sized tablet form in
5mg and 10 mg sizes, though your vet would have to order these
for you. In 2018 100 tablets cost around Ł15 (5mg) to Ł18 (10mg) for
100, plus VAT and your vet's mark up.
Australia
Unfortunately in Australia it appears the
smallest size available is now 150 mg, which is very difficult
to divide into cat-sized doses, though you may be able to use a
compounding pharmacy.
Ranitidine Dosages
One
reason why people may decide not to use ranitidine is that it
usually has to be given twice a day, whereas famotidine is
usually only given once every other day, or occasionally once a
day.
-
The
usual dose is 0.25 to 1.00 mg per pound (0.5 - 2.00 mg per kg)
every 8-12 hours, though most people find twice a day is fine.
-
You
therefore would give a 10lb (4.5kg) cat 2.5 - 10 mg twice a
day.
-
The
standard size pill is 75mg, so for a 10 lb (4.5kg) cat who is
getting the higher dose, it is usually easiest simply to give
an eighth of a tablet twice a day (i.e. 9.375 mg, or a little
under 10 mg).
-
Some people give up to twice this amount, but as with
famotidine, I suggest starting low and increasing the dose if
necessary since ranitidine is also excreted by the kidneys. Be
guided by your vet.
The effect of orally administered
ranitidine and once-daily or twice-daily orally administered
omeprazole on on intragastric pH in cats
(2015) Šutalo S, Ruetten M, Hartnack S, Reusch CE & Kook
PH Journal of Veterinary Internal Medicine 29(3)
pp840-6 used a dosage of 1.5-2.3 mg/kg twice a day. This equates
to 6.75 - 10.35 mg twice a day for a 10 lb (4.5kg) cat. However,
the study concluded "standard dosages of ranitidine were not
effective acid suppressants in cats." Nevertheless, I do hear
from people who find ranitidine effective.
Ranitidine tastes quite bitter and can make cats foam at the
mouth, so you may find it easier to give it in a
gelatine capsule (gelcap). Many people prefer to give the
second dose of the day at bedtime because this seems to help
cats who vomit at night or first thing in the morning. It
usually takes effect pretty quickly, within a couple of days.
As
with famotidine, some people find that after a while, ranitidine
seems to be less effective. Speak to your vet about either
increasing the dose or frequency or using another treatment as
well as or instead of the ranitidine.
Ranitidine
Side Effects and Interactions
Ranitidine may cause vomiting and diarrhoea in some cats.
Plumb's Veterinary Drug
Handbook recommends separating ranitidine from
phosphorus binders but
Therapy of gastrointestinal ulcers
(monogastric) (2015)
Dowling PM Merck Veterinary Manual says ranitidine can be
given at the same time as low doses of phosphorus binders. It
does recommend separating ranitidine from
sucralfate (Carafate or Antepsin)
Chronic kidney disease (CKD) in dogs and cats — staging and
management strategies
(2015) Chew D Presentation to the Virginia Veterinary Medical
Association 2015 Virginia Veterinary Conference states that
"Calcium carbonate binds phosphorous [sic] best in an
acidic environment (pH approx. 5) and binding capacity is
reduced in the neutral pH range. Many CKD patients receive
inhibitors of gastric acid secretion potentially reducing
calcium carbonates ability to bind phosphorous." I did use
calcium-based binders and famotidine with Ollie with no
problems, but if you are using ranitidine in addition to
calcium-based phosphorus binders such as Ipakitine or Pronefra,
I would discuss the situation with your vet.
Ranitidine can interfere with antibiotics in the cephalosporin
family such as
cefovecin (Convenia), so you should separate the two
treatments by two hours. H2-antagonist
cephalosporin interactions (2003) Ali A Thesis states
"These interaction studies with H2-receptor antagonists in
gastric as well as blood pH revealed that simultaneous use of
these drugs depressed the availability of the antibiotic as well
as cimetidine, ranitidine and famotidine." Plumb's Veterinary
Drug Handbook does not mention cefovecin (Convenia)
specifically, but does mention that taking other members of the
cephalosporin family with food may offset the reduced absorption
of the antibiotic.
Ranitidine may reduce the absorption of vitamin B12 from food.
Proton pump inhibitor and histamine H2
receptor antagonist use and vitamin B12 deficiency
(2013) Lam JR, Schneider JL, Zhao W & Corley DA
Journal of the American Medical Association 310(22)
pp2435-2442 found that in humans "gastric acid inhibitor use was
significantly associated with the presence of vitamin B12
deficiency." Therefore if you are using ranitidine, it might be
worth supplementing
vitamin B12.
It is
also advisable to separate ranitidine from
ACE inhibitors such as benazepril (Fortekor), but if this is
difficult for you, e.g. because of work commitments, just do the
best you can.
Please see above
for information about the withdrawal of ranitidine from the US
market and its likely withdrawal from other markets.
Proton
Pump Inhibitors (PPIs)
Proton pump inhibitors (PPIs) are also used to control acid, but do not
work in the same way as histamine H2 antagonists, which block acid after it has been
produced. Instead PPIs work by inhibiting the release of acid into the
stomach in the first place. They are therefore often used for the
treatment of stomach ulcers, but are also increasingly being used in
CKD cats.
Omeprazole (Prilosec,
Losec)
Omeprazole is the most commonly used
PPI in CKD cats.
The failure of oral stomach acid suppressants in
cats (2020) is a final report from
the Winn Feline Foundation on research comparing newer PPIs (esomeprazole,
lansoprazole, and dexlansoprazole), which found that only esomeprazole
appeared to suppress acid in cats, and it took four days to have any
effect.
Antisecretor activity of omeprazole in the conscious
gastric fistula cat: comparison with famotidine
(1989) Coruzzi G & Bertaccini G Pharmacological Research
21(5) pp499-506 found that omeprazole was "approximately fivefold less
potent than famotidine" and most effective when
the stomach was at the peak of acid production.
However,
Evaluation of the effect of orally administered acid
suppressants on intragastric pH in cats (2015) Parkinson S,
Tolbert K, Messenger K, Odunayo A, Brand M, Davidson G, Peters E, Reed A &
Papich MG Journal of Veterinary Internal Medicine 29(1)
pp104-12 found that omeprazole (in both tablet form, and a
reformulated paste form normally used for horses) appeared to be more effective than famotidine.
It also found that omeprazole is "generally well tolerated" in cats.
The effect of orally administered ranitidine and
once-daily or twice-daily orally administered omeprazole on on
intragastric pH in cats (2015) Šutalo S,
Ruetten M, Hartnack S, Reusch CE & Kook PH Journal of Veterinary
Internal Medicine 29(3) pp840-6 concluded that "twice-daily PO
[orally] administered omeprazole significantly suppressed gastric acidity
in healthy cats, whereas once-daily omeprazole and standard dosages of
ranitidine were not effective acid suppressants in cats."
So why don't I recommend starting with omeprazole rather than the
histamine H2 antagonists, such as famotidine? Well, firstly, because I've
seen the histamine H2 antagonists used for much longer, since 1999, and
most people seem to find they are effective with few side effects.
Secondly, a number of human studies have found that PPIs are associated
with a higher risk of kidney problems. See
Risks for more
information.
ACVIM consensus statement: support for
rational administration of gastrointestinal protectants to dogs
and cats (2018) Marks SL, Kook PH, Papich MG, Tolbert
MK & Willard MD Journal of Veterinary Internal Medicine
32(6) pp1823-1840 state "Despite the long list of
potential adverse effects associated with PPI treatment, the quality of
evidence underlying these associations is consistently low."
Still, I personally would feel more comfortable trying
famotidine first, though many members of Tanya's CKD Support Group do use
omeprazole in their cats with no problem.
Veterinary Partner
has some
information about omeprazole.
PetCoach also has some information.
Omeprazole Formulations
Omeprazole is available over the counter in many countries in both tablet
(omeprazole) and slow release capsule (omeprazole magnesium) form. Discuss
which formulation to use with your vet.
Omeprazole Tablets
The tablets usually come in a 20.6mg strength.
They are enteric-coated, so are not supposed to be broken up. Plumb's
Veterinary Drug Handbook (7th Edition) says
"Omeprazole capsules or tablets should not be crushed or chewed."
However,
Evaluation of the effect of orally administered acid
suppressants on intragastric pH in cats (2015) Parkinson S,
Tolbert K, Messenger K, Odunayo A, Brand M, Davidson G, Peters E, Reed A &
Papich MG Journal of Veterinary Internal Medicine 29(1)
pp104-12 found that if you split the tablets into cat-sized doses,
"enteric-coated omeprazole tables are effective for acid suppression in
spite of the disruption of the enteric coating." Some members of
Tanya's Support Group do use the tablets for their cats (split into
cat-sized doses) and find them
effective.
Drugs has a list of US brands
showing whether they are tablets or capsules.
Walgreens sells 42 tablets in the 20.6mg
strength for US$21.99. Sometimes it offers buy one, get one half price
deals.
Boots in the UK sells 28 tablets in a
10mg strength for Ł14.99.
Omeprazole Capsules
The capsules usually come in a 20.6mg strength and contain omeprazole
magnesium. The magnesium helps to make the product delayed release, so the
omeprazole
reaches the stomach intact, where it is needed.
Magnesium is not ideal for CKD cats, but
some of the magnesium will be part of the capsule, which you discard.
However, the tiny beads are also coated because they need to reach the
stomach intact.
In
theory the capsules should not be used for cats, because slow release
medicines are not supposed to be opened, but an entire capsule is too big
for a cat. Quite a few members of Tanya's CKD Support Group have
opened and used capsules successfully for their cats. Plumb's Veterinary
Drug Handbook (7th Edition) says
"Omeprazole capsules or tablets should not be crushed or chewed. If
reducing the dose of the commercially available capsules, the capsule
contents should be re-inserted into a gelatin capsule so they cannot be
chewed." However, many people do simply mix the capsule contents with
their cat's food, see
below.
If your vet agrees to you using capsules, you will see that each capsule
contain beads (microspheres). You should open one of the capsules and
count the microspheres. The number varies depending upon the manufacturer.
Once you know how many beads your chosen product contains, you can
calculate your cat's dose. For example, if your 20mg capsule contains 100
beads, and you want to give your cat 2.5mg, you would give your cat 12-13
beads once a day.
Unfortunately many omeprazole capsules have too many beads to count,
especially in the USA). CVS sells its own version of omeprazole capsules,
but members of my support group find they usually contain tiny beads
which seem to carry a lot of static and are therefore very difficult to
count. One group member did count them though, and found there were close
to 3000 beads in one capsule! Walgreens used to sell reasonable capsules
but recently they seem to be a tablet within a capsule. Kroger apparently sells a generic form of omeprazole with not too
many beads, though not everybody has had success in finding them. Altosec generic capsules apparently only contain about twenty
beads.
Drugs has a list of US brands
showing whether they are tablets or capsules.
Vet Rx Direct sells omeprazole capsules
for 36 cents each (10g) and 53 cents (20mg). A member of Tanya's Support
Group tells me these contain countable beads. A prescription is required.
Omeprazole Compounded
Some people prefer to have omeprazole compounded into capsules or a liquid
for their cats. Plumb's Veterinary Drug Handbook (2011) states "Use
caution when using compounded omeprazole products; bioequivalence has been
an issue with some compounded preparations." Nevertheless, some members of
Tanya's Support Group do use compounded omeprazole without problems.
Omeprazole Dosage
Omeprazole Dosage: Amount
Pet Place states that "The typical dose
administered to animals is 0.25 to 0.5 mg per pound (0.5 to 1.0 mg/kg),
every 24 hours or once daily." Based on the per pound dosage, a 10 lb
(4.5kg) cat would receive 2.5 to 5 mg once a day (which is actually a
little more than 0.5 to 1.0 mg/kg).
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016) Sparkes AH,
Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C,
Lefebvre H, White J & Quimby J Journal of Feline Medicine and Surgery
18 pp219-239 recommend "0.5–1 mg/kg q12–24h PO," which would mean a
10 lb (4.5kg) cat would receive 2.5 to 5 mg once or twice a day.
The effect of orally administered ranitidine and
once-daily or twice-daily orally administered omeprazole on on
intragastric pH in cats (2015) Šutalo S,
Ruetten M, Hartnack S, Reusch CE & Kook PH Journal of Veterinary
Internal Medicine 29(3) pp840-6 used a dosage of 1.1-1.3 mg/kg,
in which case a 10 lb (4.5kg) cat would receive 5 to 5.85 mg.
Many people on Tanya's CKD Support Group start with a dose of 1 mg/kg, so a 10lb (4.5kg) cat would receive 4.5 mg.
Omeprazole is excreted via the liver and kidneys, so
speak to your vet about a
suitable dose for your cat, especially if your cat has more advanced
kidney disease.
Omeprazole Dosage: Frequency
Previously omeprazole was dosed once daily.
A recent study,
The effect of orally administered ranitidine and
once-daily or twice-daily orally administered omeprazole on
intragastric pH in cats (2015) Šutalo S,
Ruetten M, Hartnack S, Reusch CE & Kook PH Journal of Veterinary
Internal Medicine 29(3) pp840-6, assessed the effectiveness of once daily versus twice daily
dosing and concluded that "twice-daily PO [orally] administered omeprazole
significantly suppressed gastric acidity in healthy cats, whereas
once-daily omeprazole and standard dosages of ranitidine were not
effective acid suppressants in cats."
This study looked at the use of omeprazole in a small group of healthy
cats. Whether the same approach is appropriate for CKD cats is debatable,
bearing in mind that omeprazole is excreted via the liver and kidneys, and
there are other possible side effects and risks (see below).
Nevertheless,
ISFM consensus guidelines on the diagnosis and
management of feline chronic kidney disease (2016) Sparkes AH,
Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C,
Lefebvre H, White J & Quimby J Journal of Feline Medicine and Surgery
18 pp219-239 recommend "0.5–1 mg/kg q12–24h PO," which would mean a
10 lb (4.5kg) cat would receive 2.5 to 5 mg once or twice a day.
Some members of Tanya's CKD Support
Group have started (with their vets' approval) to give omeprazole twice a
day rather than once. Many of those I hear from think this helps their cats, but as ever, be guided by your
vet regarding the best approach for your cat.
Omeprazole Dosage: Length of Treatment
The main disadvantage with omeprazole is that in humans, it is used for 14
days only and then not used again for four months.
Plumb's Veterinary Drug Handbook mentions that it is thought to be safe to
use omeprazole in dogs for at least four weeks.
A prospective, placebo-controlled pilot evaluation
of the effect of omeprazole on serum calcium, magnesium, cobalamin,
gastrin concentrations and bone in cats (2016) Gould E,
Clements C, Reed A, Giori L, Steiner JM, Lidbury JA, Suchodolski JS, Brand
M, Moyers T, Emery L & Tolbert MK Journal of Veterinary Internal
Medicine 30(3) pp779-86 found that giving omeprazole to six
healthy cats for eight weeks did not seem to have an adverse effect on the
examined perameters, however, this was a very small study into healthy
cats.
ACVIM consensus statement: support for
rational administration of gastrointestinal protectants to dogs
and cats (2018) Marks SL, Kook PH, Papich MG, Tolbert
MK & Willard MD Journal of Veterinary Internal Medicine
32(6) pp1823-1840 state "Our consensus opinion is that
PPIs should be tapered in dogs and cats after prolonged use of >3-4
weeks."
Still, I do know of some people who have used omeprazole on an ongoing basis
with no apparent problems. Be guided by your vet as to the best course of
action for your cat.
Omeprazole: Speed of Response
Some cats respond to omeprazole within a day, but it can take up to a week
to take effect. During this period, or if omeprazole alone
does not seem to be sufficient to help your cat, your vet may ask you to
start or continue using other treatments.
It is acceptable to use omeprazole at the same time as
famotidine or ranitidine, as long as your vet approves.
Can famotidine and omeprazole be combined on a
once-daily basis? (2007) Fändriks L,
Lönroth H, Pettersson A & Vakil N Scandinavian Journal of
Gastroenterology 42(6) pp689-94 found that doing so was safe in
healthy humans, and some members of my support group do the same for their
cats.
Cats vary a lot in how effective omeprazole is for them.
The effect of orally administered ranitidine and
once-daily or twice-daily orally administered omeprazole on on
intragastric pH in cats (2015) Šutalo S,
Ruetten M, Hartnack S, Reusch CE & Kook PH Journal of Veterinary
Internal Medicine 29(3) pp840-6 states "We saw considerable
individual variation in response to treatment with omeprazole...For
example, 1 cat consistently had close to 100% acid suppression, whereas
another had extremely poor acid suppression."
Omeprazole: How to Give
Unlike acid blockers such as famotidine (Pepcid), omeprazole is tasteless.
Therefore many people just mix the correct number of beads from the
capsule formulation (see
above) with their cat's food.
Omeprazole Risks
It has been known for some time that the use
of PPIs such as omeprazole has been associated with a higher risk of
acute kidney
injury. In 2016 a human study,
Proton pump inhibitor use and the risk of chronic
kidney disease (2016)
Lazarus B, Chen Y,
Wilson FP, Sang Y,
Chang AR, Coresh J &
Grams ME Journal of the American Medical
Association Internal Medicine 176(2) pp238-246
reviewed the use of PPIs in humans and found that "Proton pump
inhibitor use is associated with a higher risk of incident CKD.
Future research should evaluate whether limiting PPI use
reduces the incidence of CKD."
The authors further state "Use of PPIs may lead to
chronic kidney disease through recurrent acute kidney injury or
hypomagnesemia."
The risk was higher when the PPIs were taken twice a day rather than once
a day.
An unexpected effect of proton pump inhibitors:
elevation of the cardiovascular risk factor ADMA
(2013) Ghebremariam YT, LePendu P, Lee JC, Erlanson DA, Slaviero
A, Shah NH, Leiper J & Cooke JP Circulation 128(8) pp845-53
found that proton pump inhibitors may increase the risk of major adverse
cardiovascular events. However, in a later study,
Proton pump inhibitors and vascular function: a
prospective cross-over pilot study
(2015) Vascular Medicine 20(4) pp309-316 found that "PPI use
[Prevacid] did not significantly influence vascular endothelial function.
Larger, long-term and blinded trials are needed to mechanistically explain
the correlation between PPI use and adverse clinical outcomes, which has
recently been reported in retrospective cohort studies."
Analysis of postmarketing safety data for
proton-pump inhibitors reveals increased propensity for renal injury,
electrolyte abnormalities, and nephrolithiasis
(2019) Makunts T, Cohen IV, Awdishu L & Abagyan R Nature
Scientific Reports 9(2282) checked over 10 million FDA Adverse
Event Reporting System records and concluded that PPIs increased the risk
of CKD and acute kidney injury in humans. It states "Although H2RAs have
not been shown to be as effective as PPIs, they might be considered as
alternatives for patients who are at high risk of developing renal and
electrolyte imbalances."
However,
ACVIM consensus statement: support for
rational administration of gastrointestinal protectants to dogs
and cats (2018) Marks SL, Kook PH, Papich MG, Tolbert
MK & Willard MD Journal of Veterinary Internal Medicine
32(6) pp1823-1840 state "Despite the long list of
potential adverse effects associated with PPI treatment, the quality of
evidence underlying these associations is consistently low."
Omeprazole Side Effects
and Interactions
According to Plumb's Veterinary Handbook, possible side effects include
nausea, vomiting and diarrhoea. Urinary tract infections,
proteinuria or central nervous system disturbances may also be seen.
Omeprazole may also cause a low white blood cell count (neutrophils),
though this is rare.
The US Food & Drug Administration
(2011) states that the long term use (usually for more than a year) of
medications such as omeprazole may lead to decreased
magnesium levels in the body which cannot necessarily be corrected
with magnesium supplements
One known problem with proton pump inhibitors is that they may inhibit the
absorption of nutrients from food, particularly Vitamin B12 and calcium. It is
recommended that omeprazole should only be used in humans for eight weeks.
Proton pump inhibitor and histamine H2 receptor
antagonist use and vitamin B12 deficiency
(2013) Lam JR, Schneider JL, Zhao W
& Corley DA Journal of the American Medical Association 310(22)
pp2435-2442 found that in humans "gastric acid inhibitor use was
significantly associated with the presence of vitamin B12 deficiency."
Adverse effects of long-term proton pump inhibitor
therapy (2011) Sheen E & Triadafilopoulos G Digestive
Diseases & Sciences 56(4) pp931-50 mentions that long term use
in humans is becoming increasingly common and reviews the possible adverse
effects of long term use. The study concluded that the benefits of longer
term treatment outweigh the risks for most patients, but that elderly or
chronically ill patients "theoretically could be at increased risk from
long-term therapy." Therefore if you use it for any length of time, ask
your vet if you should start or increase a
vitamin B12
supplement.
Retrospective analysis of the effect of
acid-suppressant therapy on clinicopathologic parameters of cats
with chronic kidney disease (2018) Gould E,
Klos J, Price J, Harris T, Vaden S & Tolbert MK Journal of
Feline Medicine and Surgery 20(6) pp520-527 looked at
the effects of acid suppressant therapy (acid blockers, proton
pump inhibitors and both combined) in CKD cats. It concludes "A
significant increase in blood sodium concentration (change of
3.12 mmol/l) was found independent of stage in cats receiving
PPI therapy." However, the use of acid blockers did not seem to have any adverse
effect on the progression of the CKD.
If omeprazole is stopped, there may be a rebound effect, i.e. there may
be an increase in stomach acid production that is higher than that before
the treatment was begun. This can last a couple of weeks.
Web MD talks more about this.
Cautions
Mirtazapine
Mirtazapine (trade name is Remeron
in the USA and Zispin in the UK) is an anti-depressant but it can
also
cause an increase in appetite, and it may also have anti-emetic
(anti-vomiting) properties according to
Mirtazapine as an appetite stimulant and anti-emetic
in cats with chronic kidney disease: a masked placebo-controlled crossover
clinical trial
(2013) Quimby JM & Lunn KF Veterinary Journal
197(3) pp651-655, which found that "the
oral administration of 1.88 mg [⅛
of a 15mg tablet]
of mirtazapine every other
day for 3 weeks to cats with CKD resulted in significantly increased
appetite. Additionally, significant weight gain, increased activity and
decreased vomiting were demonstrated."
Although mirtazapine can be a very effective appetite stimulant, I am
concerned that cats may be offered mirtazapine and nothing else discussed on this page. I am
always nervous about the use of appetite
stimulants because whilst some cats may eat
because of such medications, they could be doing so
despite still
feeling
horrible. I think it is extremely important to ensure that the cat is not
only eating, but is also as comfortable as possible.
I would certainly not rule out using mirtazapine, which
can be very helpful for CKD cats and which is discussed in detail
here, but
please do also talk to your vet about whether any of the other treatments
discussed on this page should also be used.
Cimetidine (Tagamet)
You may be offered cimetidine, which, like
famotidine and
ranitidine, is a
histamine H2
antagonist.
Cimetidine has many more drug interactions than either famotidine
or ranitidine, including with
amlodipine (a calcium channel blocker used to treat
heart disease or high blood pressure), and
diazepam (Valium), which is
sometimes used as an appetite stimulant. It also has the most marked
rebound effect (a temporary increase in stomach acid) if it is stopped.
I would therefore suggest using famotidine or ranitidine instead.
Pet Place has information about
cimetidine
If you do use cimetidine,
The Merck Veterinary Manual
(link does not work in UK) recommends separating it from
phosphorus
binders and from
sucralfate (Carafate
or Antepsin).
Chronic kidney disease (CKD) in dogs and cats — staging and management
strategies (2015) Chew D
Presentation to the Virginia Veterinary Medical Association 2015 Virginia
Veterinary Conference states that "Calcium
carbonate binds phosphorous [sic] best in an acidic environment (pH approx. 5)
and binding capacity is reduced in the neutral pH range. Many CKD patients
receive inhibitors of gastric acid secretion potentially reducing calcium
carbonates ability to bind phosphorous." I did use calcium-based
binders and famotidine with Ollie with no problems, but if you are using
cimetidine in addition to
calcium-based phosphorus binders such as Ipakitine or Pronefra, I would discuss the situation with your vet.
Cimetidine can interfere with antibiotics in the
cephalosporin family such as
cefovecin (Convenia), so you should separate the two treatments by two hours.
H2-antagonist cephalosporin interactions
(2003) Ali A Thesis states "These interaction studies with H2-receptor antagonists in
gastric as well as blood pH revealed that simultaneous use of
these drugs depressed the availability of the antibiotic as well
as cimetidine, ranitidine and famotidine."
Cimetidine may reduce the absorption of vitamin B12 from food.
Proton pump inhibitor and histamine H2 receptor
antagonist use and vitamin B12 deficiency
(2013) Lam JR, Schneider JL, Zhao W & Corley DA Journal of the American Medical Association 310(22)
pp2435-2442 found that in humans "gastric acid inhibitor use was
significantly associated with the presence of vitamin B12 deficiency."
Therefore if you are using cimetidine, it might be worth supplementing
vitamin B12.
The effects of cimetidine on renal function in
patients with renal failure (1980)
Larsson R,
Bodemar G,
Kagedal B,
Walan A
Acta medica Scandinavica 208 (1-2) pp27-31 explains that
cimetidine may cause an increase in creatinine levels. If your
cat's creatinine levels rise while using cimetidine, you may find they
improve once you stop the medication.
Top ten potential drug interactions on dogs and cats
(2008) Trepanier LA Presentation to the World Small Animal Veterinary
Association World Congress recommends using famotidine or ranitidine
rather than cimetidine, as do I.
Metoclopramide (Reglan
or Emeprid)
Metoclopramide is a prescription medication which works by regulating
stomach contractions. This means it can help with nausea caused by a lack
of motility in the stomach.
Pet Place has some information about
gastric motility problems in cats.
Since metoclopramide can cross the blood/brain barrier, it also acts on
the brain to control feelings of nausea. However, it appears that it is
not actually particularly effective in cats.
Current approaches to vomiting in cats and puppies
(2013) Gaschen FP, Lee JA, Parnell N, Richter K, Tams TR, Twedt D & Gloyd
K Pfizer Roundtable Discussion states "I
don’t use metoclopramide in cats anymore. I am not completely convinced it
is that effective as an antiemetic
in cats. Evidence suggests that cats don’t have dopamine receptors in the
chemoreceptor trigger zone, which
is metoclopramide’s site of action."
When I first set up this website in 2000, quite a few people used
metoclopramide for their cats if the
histamine H2
antagonists were not
sufficient. I do not recall there being too many problems with the
medication over subsequent years. In 2009, the
US Food and Drug Administration issued a warning regarding the
chronic use of metoclopramide because this had been linked to a condition called tardive
dyskinesia, i.e. involuntary and repetitive movements of the body, which
may continue even after the treatment is stopped. One such movement
mentioned by the FDA is
lipsmacking (although it should be noted that lipsmacking in
CKD cats
is normally caused by excess stomach acid or nausea,
anaemia
or
dehydration).
The FDA therefore recommends that products containing metoclopramide
should not be used for longer than three months.
In July 2013 the
European Medicines Agency went further
and announced that metoclopramide should only be used short term (up to
five days) and that it should only be used in adults "for the
prevention and treatment of nausea and vomiting such as that associated
with chemotherapy, radiotherapy, surgery and in the management of
migraine." In addition, it recommended that dosages should be lowered.
Obviously these
warnings apply to humans, but since there are now other treatments
available as outlined above which are far more effective and carry fewer risks, I would only use
metoclopramide as a last resort. Be sure to discuss these warnings with
your vet before using metoclopramide.
Veterinary Partner has more information on metoclopramide.
Pet Place
also has some information.
Metoclopramide Dosages
Metoclopramide comes in
10 and 5mg tablets or a liquid. Injectable metoclopramide is also
available as 5mg/ml in 2 ml or 10 ml vials. It must be
given 20-30 minutes before eating.
A typical dose would be 0.1 to 0.2 mg per pound (0.2 to 0.5 mg per kg)
every six to eight hours, so a 10lb (4.5kg) cat would get 1 mg to 2 mg at
a time. Plumb's Veterinary Drug Handbook mentions that dosages may need to
be reduced in animals with kidney disease, so be guided by your vet.
Metoclopramide Side Effects and Interactions
Please see the important warning above.
Metoclopramide may have various side effects,
including constipation, hyperactivity and agitation or drowsiness.
Metoclopramide also lowers the seizure
threshold, so should not be given to cats prone to
seizures.
Drugs mentions that it may increase the risk of bronchospasm in asthmatics, and
intravenous metoclopramide may worsen hypertension (high blood pressure).
I used to recommend giving metoclopramide at least two hours apart from
famotidine (Pepcid AC) or
ranitidine (Zantac 75)
because, according to
Plumb's Veterinary Drug Handbook,
the metoclopramide could bind with these other medications and reduce
their effectiveness. However, the most recent edition of Plumb's does not
mention this interaction, so it appears that you do not need to separate
metoclopramide from these other medications after all.
Using metoclopramide as well as
mirtazapine (appetite stimulant) increases the risk of serotonin
syndrome. You can read more about this and what to watch for
here.
Drs Foster and Smith
have some information about possible side effects. They also
mention that metoclopramide is similar to PABA, the sunscreen component,
so people who are allergic to PABA should not touch metoclopramide.
Pepto-Bismol
Please do not use Pepto-Bismol. It contains a type of salicylate,
similar to what is found in aspirin, and cats are not able to metabolise
this easily, so it may be fatal even in small doses.
Pet Place warns against using
Pepto-Bismol in cats.
Antacids
Some vets recommend the use of antacids, such as Tums or Mylanta. Some
products in this family do actually work well in CKD cats as
phosphorus binders,
but they are not usually strong enough to help control excess stomach acid, plus
using products containing
magnesium is not usually recommended for CKD
cats, who tend to have high levels of magnesium generally.
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This page last updated: 27 October 2020
Links on this page last checked: 06 April 2020
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