Causes of Nausea, Vomiting and Appetite Loss


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Fluid and Urinary  Imbalances (Dehydration, Overhydration and Urinary Issues)

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Miscellaneous Treatments: Stem Cell Transplants, ACE Inhibitors - Fortekor, Steroids, Kidney Transplants)

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General Health Issues in a CKD Cat: Fleas, Arthritis, Dementia, Vaccinations

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Home > Key Issues > Nausea, Vomiting, Appetite Loss and Excess Stomach Acid



  • Nausea, vomiting and loss of appetite are some of the most common problems in CKD cats.

  • There are a variety of possible causes, and a cat may have more than one reason for showing these symptoms.

  • 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.

  • Excess stomach acid is one of the most likely culprits in cats with creatinine over 3 (USA) or 265 (international), though it can also be a problem in cats with lower creatinine levels. There are a number of treatments that can help excess stomach acid.

  • If your cat continues to have problems despite being treated for excess stomach acid and any other possible causes, there are other treatments available which can help control nausea and vomiting.

  • Please note, excess stomach acid is not the same thing as metabolic acidosis.

Causes of Nausea, Vomiting and Loss of Appetite                                              Back to Page Index


Common Causes

Unfortunately, there are a large number of possible causes of nausea, vomiting and loss of appetite in CKD cats. It can therefore 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 not only stop the vomiting and appetite loss and help your cat feel more comfortable, it may in some cases (e.g. controlling high phosphorus levels) also help slow the progression of the CKD.


Why so many vomiting cats? Getting the diagnosis (2011) is a presentation by Dr S Little to the 36th World Small Animal Veterinary Association World Congress with a flow chart for narrowing down the cause of the vomiting.


Toxins, Including Excess Stomach Acid

Even if you rule out or treat the above causes, your cat may still continue to have problems with vomiting, nausea and appetite loss. In such cases, the problem may be caused by toxins, particularly excess stomach acid. Almost every CKD cat will have problems with stomach acid at some point, so the chances are you need to read this page even if your cat might have 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.


Gastrin is a gastro-intestinal 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 stimulating the production of too much gastric acid.


This excess stomach acid can make a cat feel very unwell. In severe cases stomach ulcers may develop, which may cause gastro-intestinal bleeding. Generally speaking, cats with creatinine over 3 (US) or 265 (international) will need help controlling excessive stomach acid.


Also, although BUN is not itself a 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 level will be, and the more likely it is that s/he will feel sick and vomit.


If your cat has relatively low kidney bloodwork values (in the 2s or low 3s in US terms, 200-300 international) but nevertheless seems to vomit a lot, I would ask your vet to rule out pancreatitis.


Symptoms                                                                                                           Back to Page Index


There is no test as such for excess stomach acid or other 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):


Loss of Appetite

Loss of appetite is very common in CKD cats, and is often linked to excess stomach acid. 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 medicationDental problems may also cause appetite loss.


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 inappetance and treat it as quickly as possible. 



Nausea can be hard to detect, though it is often manifested in a lack of appetite. The cat may also lie scrunched up, looking uncomfortable.


High phosphorus levels, dehydration or anaemia may also cause nausea.



CKD cats often vomit. Vomiting may be seen alone or in conjunction with the other symptoms in this section. Many cats with excess stomach acid or uraemia vomit regularly without treatment.


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 gastro-intestinal 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. The American Association of Feline Practitioners explains the difference and links to a number of sites, including one with a video of a cat vomiting.


Cats who vomit immediately after eating may have a gastric motility problem - ranitidine may help with this.


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.


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.

Diagnosis and management of acute and chronic vomiting in dogs and cats (2007) is a paper by Dr TR Tams.

Managing vomiting in cats: what's new for an old problem (2008) Zoran DL Presentation to the 2008 Nestlé Purina Veterinary Symposium has an overview of vomiting in cats.


Vomiting White Foam

Vomiting does not just include food - the classic symptom of excess stomach acid 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, them 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.


Lip Licking

This can be a sign of nausea and excess stomach acid. It may also be a sign of dehydration. 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 excess stomach acid. 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 Dental Center of Milwaukee and Oshkosh discusses the various causes of teeth grinding in cats.

Youtube has a video of a cat grinding his/her teeth.



CKD cats may occasionally become rather hoarse because of acid reflux caused by excess stomach acid. 


In some cases it 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 cats may have excess stomach acid. Dental problems or mouth ulcers may also  cause drooling. Manhattan Cat Specialists have more information about drooling.


Eating Grass

Cats commonly eat grass in order to help themselves vomit. They often do this if they want to bring up a hair ball, and this is sometimes also the reason why CKD cats eat grass. However, CKD cats do tend to feel nauseous generally, because of the disease rather than because of hair balls, and if you feel nauseous, you may feel a little better if you can actually vomit. Therefore CKD cats who feel nauseous may eat grass in order to make themselves 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 excess stomach acid. Howling may have other causes (see Index of Symptoms and Treatments). 


Hunched over Water Bowl

This can be a sign of nausea and excess stomach acid. 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 excess stomach acid. 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 excess stomach acid, 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 excess stomach acid.


Increased Drinking

Increased drinking is common in CKD cats because they usually have problems maintaining hydration. However, it can also be a symptom of excess stomach acid. In some cases it may indicate diabetes.


Licking Gravy Only

The cat may lick the gravy only and leave any solid food behind. However, this may not indicate excess stomach acid 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 excess stomach acid have sore tummies, they may sit in a hunched up, uncomfortable position. In the worst case, this may indicate crashing, but only if you also see the symptoms described there.


Treatments                                                                                                          Back to Page Index


The best treatment for vomiting, nausea and loss of appetite depends upon the cause of the problem. This page focuses on treatments for these problems caused by toxins including excess stomach acid. You can check the Index of Symptoms and Treatments page for information on treatments for the other possible causes mentioned above.


Although it is not possible to test for toxins, particularly excess stomach acid, if your cat is showing any of the symptoms described above (e.g. vomiting white foam), it is usually worth treating for it, and seeing if your cat feels better. Here is a possible staged treatment plan for you to discuss with your vet:

  1. Firstly, try these simple natural treatments - for some cats, especially those in early stage CKD, these are the only treatments they need:

  1. If these treatments don't seem to be helping after a couple of days, move onto the histamine H2 antagonists (acid blockers), which are a group of medications commonly used to control excess stomach acid. These help the vast majority of cats. You can use these in conjunction with the natural treatments.

  1. If your cat is still struggling, consider anti-nausea medications. These medications are usually very effective for nausea and vomiting, and may be the best choice for cats with additional issues, such as gastric mobility, or cats with concurrent pancreatitis or IBD. They can usually be used in conjunction with the medications outlined above:

It is usually safe to use more than one of these treatments at the same time, e.g. slippery elm bark and famotidine, but check with your vet first. Don't use Pepto-Bismol or  antacids such as Tums or Mylanta.


How I treat uremic crises in dogs and cats with chronic kidney disease (2009) is a presentation by Dr D Polzin to the 34th World Small Animal Veterinary Association World Congress which discusses various treatments.


Natural Treatments                                                                                                                       Back to Page Index

The beauty of these treatments is that they need little effort, are not particularly invasive and require very little outlay, yet for some cats they are extremely effective. I therefore recommend trying them to see if they help. If they are going to help, you would normally see a difference (e.g. reduced vomiting) within a couple of days.

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 sells raised stoneware bowls for about US$25. I have some of these, and my cats love them. My cats do not have CKD, but I have noticed they eat more if I feed them from these bowls.

Drs Foster & Smith sell a cast iron raised food bowl stand from US$17.99. They also sell some other raised bowls.


Feeding Before Bedtime

You may find that your cat has more stomach upsets at night which cause vomiting during the night or first thing in the morning. This happens because if a cat goes a long time without eating, the excess stomach acid has more time to attack the stomach lining.


In addition to using the other treatments mentioned here, 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

If you wish to pursue natural methods of controlling stomach acid and the accompanying vomiting, nausea and loss of appetite, a herbal remedy called slippery elm bark (SEB) is often very effective. 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.


Use of Acid Blockers (Histamine H2 Antagonists)                                                    Back to Page Index

This is a group of medications which can be most effective in controlling excess stomach acid, which can greatly reduce vomiting and nausea and increase appetite.


Most of these medications are thought of as antacids, although in fact technically speaking they are histamine H2 antagonists that block the production of stomach acid rather than neutralise it. Because they are long-acting, they are generally a good choice for treating stomach acid problems. In Current concepts for the management of chronic renal failure in the dog and cat - early diagnosis and supportive care (2005) Presentation to the 30th World Congress of the World Small Animal Veterinary Association, Dr Sherry Sanderson mentions that it is generally recommended to use such treatments once creatinine is over 3 (USA) or 265 (international).


Although these medications can be purchased over the counter, please do NOT give them without first discussing them with your vet, particularly if your cat has advanced CKD, because they are excreted by the kidneys so may not be appropriate. Avoiding Adverse Drug Reactions (2001), a paper presented by Lauren Trepanier  to the World Small Animal Veterinary Association World Congress 2001, mentions that it is wise to reduce the dose of these medications in CKD cats (scroll to the end).


Once you start giving these medications, it is usually better to continue giving them regularly even if your cat appears better, so the excess stomach acid cannot start building up again.


Famotidine (Pepcid AC)

Famotidine (Pepcid AC) is the most commonly used medication for feline CKD-related stomach acid problems in the USA, and it is a very effective treatment for excess stomach acid. 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.


The active ingredient in Pepcid AC is famotidine USP, and Pepcid AC (Regular Strength) contains 10mg. 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.


If you opt for the brand name, there are quite a few Pepcid products available these days 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).


Unfortunately, Pepcid AC has been discontinued in the UK, having been 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; 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 £5-65 (search for Pepcid AC or famotidine). You can also obtain it in compounded cat-sized form from The Specials Laboratory - 90 2.5mg capsules cost £93.79 plus VAT and shipping costs of around £12.50. They also sell 100ml of famotidine 2.5mg per ml for £91.89, with a 90 day expiry from manufacture. If you don't want to pay those prices, I would consider using ranitidine instead.


Famotidine Dosages

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. The US Food & Drug Administration has information about the need to reduce the normal dose in (human) CKD patients. Avoiding Adverse Drug Reactions (2001), a paper presented by Lauren Trepanier to the World Small Animal Veterinary Association World Congress 2001, mentions that it is wise to do the same with CKD cats (scroll to the end).


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, Fri)

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). It usually takes effect pretty quickly, within a couple of days for most cats.


Famotidine Oral Suspension

If your cat is hard to pill, famotidine is also available as an injectible or an oral suspension (liquid).


Thriving Pets sells a 10mg/ml oral suspension (liquid) version of famotidine in a 30ml size, so if you want to give the usual famotidine dose of 2.5mg, you would give 0.25ml. This product has a short shelf life, so you should not order more than 14 days worth at a time (including delivery).  Like the pills, this form of famotidine is also very bitter, so if you don't want to give your cat bitter oral medications, consider using injectible famotidine instead. If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$55 after the discount.


Famotidine Injectible

There are two types of famotidine injectible. 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 should be kept in the fridge.


You can use the injectible 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. It is safe to take it out about 30 minutes before using it so it can warm up a little before use.

Thriving Pets sells the 10mg/ml injectible form of famotidine in a 20ml size, so if you want to give the usual famotidine dose of 2.5mg, you would give 0.25ml. If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$55 after the discount.


Famotidine Side Effects and Interactions

The most common side effects in humans are constipation or diarrhoea.


Some cats, particularly those with high bloodwork (creatinine over 5 USA, 450 international), do not 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 ranitidine.


Famotidine may adversely affect cats with existing heart rhythm problems. In such cases you may wish to ask your vet about using ranitidine instead.


Medicine Net mentions that famotidine may cause anaemia in humans. Web MD reports that human CKD patients on famotidine may exhibit abnormal levels of drowsiness.


Famotidine can interfere with antibiotics in the cephalosporin family such as Convenia, so you should separate the two treatments by two hours.


Famotidine may reduce the absorption of vitamin B12 from food, so 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.


Veterinary Partner has more information on famotidine, and mentions how it may adversely affect cats with heart rhythm problems.

Pet Place has more information about famotidine (no need to register to read the article, just click on Close at the bottom of the pop-up).

The Merck Manual has more information about famotidine and its possible side effects in humans.


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 USA, 450 international).


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.


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.

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.


The main problem with ranitidine is dividing the tablets up into cat-sized dosages. 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.


Ranitidine Oral Suspension

There is also a liquid (syrup) form of ranitidine, but this is peppermint flavoured, so not many cats would like it, plus you need a prescription for it. However, I understand you can obtain it in a beef flavoured compounded suspension from Thriving Pets. If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$55 after the discount.


Ranitidine Injectible

There is also a prescription only injectible form of ranitidine made by Bedford Laboratories, obtainable from most US pharmacies (they may need to order it for you, and it seems to go out of stock quite regularly in recent times). 


Injectible ranitidine comes in a 25mg/ml strength, usually in a 6ml vial. You can either inject this directly into your cat, or  if your cat is on sub-Qs, add it to the injection port of your IV line. A possible dose is 0.3ml twice a day, but ask your vet. Injectible ranitidine usually needs to be refrigerated but it is safe to take it out about 30 minutes before using it so it can warm up a little before use.


Thriving Pets sells injectible ranitidine. If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$55 after the discount.

Ranitidine Side Effects and Interactions

Ranitidine may cause vomiting and diarrhoea in some cats. Like famotidine, it should be used in caution in cats with heart murmurs.


Plumb's Veterinary Drug Handbook recommends separating ranitidine from phosphorus binders but The Merck Veterinary Manual say ranitidine can be given at the same time as low doses of phosphorus binders. It does recommend separating ranitidine from sucralfate (Carafate or Antepsin)


Ranitidine may reduce the absorption of vitamin B12 from food, so it might be worth supplementing vitamin B12.

It is also advisable to separate ranitidine from ACE inhibitors such as Fortekor, but if this is difficult for you, e.g. because of work commitments, just do the best you can.


Pet Place has more information about Zantac (no need to register to read the article, just click on Close at the bottom of the pop-up).


Cimetidine (Tagamet)

You may be offered another drug in this family called cimetidine. 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. 


If you do use cimetidine, The Merck Veterinary Manual recommends separating it from phosphorus binders and from sucralfate (Carafate or Antepsin).


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.

Pet Place has information about cimetidine (no need to register to read the article, just click on Close at the bottom of the pop-up).


Other Treatments                                                                                                  Back to Page Index

If the natural treatments above don't work, and your cat does not respond too well to acid blockers such as famotidine, or perhaps shows some improvement but still vomits fairly frequently,  you may need to consider trying one of these other medications. These medications treat nausea and/or vomiting but they all work in different ways, so discuss with your vet whether one of them might be suitable for your cat.


Treating feline pancreatitis (2009) Robertson J DX Consult 2(1) offers a brief overview of these three treatments.

Pharmacologic control of vomiting (2009) Tams TR CVC in Kansas City Proceedings discusses the use of these medications and others in cats.


Omeprazole (Prilosec, Losec)

Omeprazole belongs to a family of drugs known as proton pump inhibitors (PPIs). These medicines are not acid blockers like famotidine (Pepcid), but instead work by inhibiting the release of acid into the stomach on an ongoing basis. Acid blockers cannot block stomach acid production completely, but PPIs can. They are therefore often used for the treatment of stomach ulcers.


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." It found that omeprazole was most effective when the stomach was at the peak of acid production. However, if for some reason your cat does not respond well to acid blockers such as famotidine, you could ask your vet about trying omeprazole.


Pet Education has some information about omeprazole.

Veterinary Partner also has some information.


Omeprazole Formulations

Omeprazole is available in both tablet and slow release capsule form. 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. However, several members of Tanya's CKD Support Group have opened and used capsules successfully for their cats. Discuss which formulation to use with your vet.


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.


It is not always easy to find the capsule form of omeprazole but here are two sources in the USA:


Walgreens sells 42 20.6mg strength capsules for US$21.99


Amazon sells 42 20.6mg strength capsules for US$23.88.


Omeprazole Dosage

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." Thus a 10 lb (4.5kg) cat would receive 2.5 to 5 mg once a day.


Omeprazole is excreted via the liver and kidneys, so it may be necessary to adjust the dose downwards in CKD cats. Speak to your vet about a suitable dose for your cat.


Unlike acid blockers such as famotidine (Pepcid), omeprazole is tasteless. Therefore most people just mix the correct number of beads with their cat's food.


Some cats respond to omeprazole within a day, but it can take up to a week for omeprazole to take effect. During this period, your vet may ask you to continue using other treatments such as famotidine, until the omeprazole has kicked in.


Omeprazole Side Effects

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.


One known problem with proton pump inhibitors is that they may inhibit the absorption of nutrients, particularly Vitamin B12 and calcium. It is recommended that omeprazole should only be used in humans for eight weeks. 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 this approach. 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."


Plumb's Veterinary Drug Handbook mentions that it is thought to be safe to use omeprazole in dogs for at least four weeks. I have been unable to find a recommendation for length of treatment in cats, though I do know of some people who have used it on an ongoing basis. Be guided by your vet as to the best course of action for your cat. If you use it for any length of time, ask your vet if you should start or increase a vitamin B12 supplement.


Once 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. Web MD talks more about this.


Ondansetron (Zofran)

This drug is commonly used to control vomiting in cats with pancreatitis or cancer. I first heard of somebody using ondansetron for a CKD cat in 2002, but it has not been 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 quite popular for use in CKD cats, not least because it is very effective. Its trade names include Zofran in the USA, Setronon in Europe and Emeset in the UK.


Ondansetron works in a different way to metoclopramide below (it selectively inhibits serotonin 5HT3 receptors), so it does not lower the seizure threshold as metoclopramide does. 


The Merck Veterinary Manual has some brief information about ondansetron.


Some people use another drug in this family, dolasetron (Anzemet), which only needs to be given once a day, but dolasetron seems to be more commonly used at this time for cats with pancreatitis. Pharmacologic control of vomiting (2009) Tams TR CVC in Kansas City Proceedings has some information about dolasetron. 


Ondansetron Dosages

Ondansetron comes in 4mg pills, and a commonly used dose is 1 mg each day, so one pill contains four doses. This works well for many CKD cats; however, Pet Place mentions that the usual dose for cats is 0.11mg per pound bodyweight every 8-12 hours, so the usual dose may not be sufficient for some cats, particularly those with pancreatitis. If you find this is the case, speak to your vet about increasing the dose as outlined by Pet Place.


The pills are tiny, so can be hard to cut into quarters. 


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 much more cheaply. Costco apparently sell 60 4mg tablets for around US$23.


Good RX allows you to search for discounted medications in your area. As an example, I found 30 ondansetron 4mg for less than US$14 in NYC.

Health Warehouse sells 30 ondansetron 4mg tablets for US$22 including shipping, but the first order can take up to two weeks.

Thriving Pets sells ondansetron for US$1 per 4mg pill, or 80 cents each if you buy thirty. A prescription is required. If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$60 after the discount.

Pharmplex Direct in the UK sells ondansetron for £6.24 for 30 plus shipping (total cost is a little under £10). A prescription is required.


Ondansetron Injectible

There is also an injectible form of ondansetron. Thriving Pets sells 10 vials (4mg/2ml) for US$25. If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$55 after the discount.


Unfortunately injectible 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.


Ondansetron Interactions and Side Effects

Possible side effects include constipation, low blood pressure and sleepiness. Humans have reported bad headaches. Drugs has more information about possible side effects.


Ondansetron may also cause heart arrhythmias. In September 2011 The US Food & Drug Administration reported that "Ondansetron may increase the risk of developing abnormal changes in the electrical activity of the heart, which can result in a potentially fatal abnormal heart rhythm." 


Ondansetron inhibits the analgesic effects of tramadol: a possible 5-HT3 spinal receptor 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.


Maropitant (Cerenia)

Maropitant (Cerenia) is a relatively new treatment from Pfizer. The injectable form is approved for the treatment of vomiting and nausea in cats (and dogs) in the USA. In some parts of Europe maropitant is 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.


It only needs to be given once a day and does appear to be quite effective for some cats, usually taking effect within an hour. It works by blocking the stimulation of the part of the brain that instigates vomiting. I am concerned that this might mean that the cat may still feel nausea (and therefore may not want to eat), but will not vomit. However, some people do find maropitant works better for their cats than ondansetron, so if you are not finding ondansetron to be as effective as you hoped, I would try maropitant instead.


Maropitant is available in either injectible or pill form. Both the injectible and the pill form are intended to prevent vomiting, but the injectible form is also designed to treat acute vomiting. The injectible form seems to sting some cats, and the oral form seems to taste horrible.


Drs Foster & Smith sell four 16mg tablets for US$7.99.


Maropitant Dosages

For the injectible form a commonly used dose appears to be 0.5 to 1mg per kg (2.2lbs) of body weight. A 10 lb (4.5 kg) cat would therefore receive 2.25 - 4.5mg.


For the oral form, a commonly recommended dose is 1mg per kg (2.2lbs) of body weight. 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." A 10 lb cat (4.5 kg) cat would therefore receive 4.5 mg. Most people seem to buy the 16mg size and divide it as appropriate (into quarters for a 10 lb cat).


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.


The manufacturer recommends that maropitant should only be given short term to dogs, for a maximum of five days at a time. Some people have used it in their cats for a few days, taken a break, then used it again. Plumb's Veterinary Drug Handbook mentions that the medication should be stopped for at least 48 hours in these circumstances. In the above study, it was used for fifteen days without a break in cats with no apparent problems. 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. Be guided by your vet on the best approach for your cat.  


Maropitant Side Effects and Interactions

Possible side effects include vomiting, lethargy, diarrhoea, twitching and drooling.  Maropitant should not be used if there is any gastro-intestinal obstruction, and should be used with caution if liver or heart problems are present.

The European Medicines Agency 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." The University of Zürich Institute for Veterinary Pharmacology and Toxicology also mentions this (in German). 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, but check with your vet.


The European Medicines Agency also warns that urgent medical attention should be sought if maropitant gets in the eyes. The University of Zürich Institute for Veterinary Pharmacology and Toxicology also mentions the issue of eye irritation.


Pfizer product information sheet (tablets) mentions that maropitant should only be given for five days. It also states that maropitant may interact with phenobarbital, used to control epilepsy, and NSAIDs.

Pfizer product information sheet (injectible) also mentions this.

Veterinary Partner has some information about the use of maropitant in dogs, which explains more about its mechanism.

Drs Foster and Smith have an information sheet about the use of maropitant in dogs.


Maropitant Research Study

The Veterinary Teaching Hospital at Colorado State University is seeking volunteers for a study into the use of maropitant for the treatment of nausea and vomiting in cats with CKD. Cats that have been diagnosed with stable chronic kidney disease and who have a “picky” appetite, nausea or vomiting, are potentially eligible for entry into this study. Cats with other illnesses may not be eligible.


The cat will be given a complimentary physical exam and chemistry panel at the beginning of the study. The study involves giving cats either maropitant or a placebo daily for two weeks. After two weeks, the cat will receive a second complimentary physical exam and complimentary blood tests (blood chemistry panel). During the study, the owner will be asked to fill out a daily diary of the cat’s behavior and other details. Owners receive complimentary veterinary visits and chemistry tests; a $100 stipend is offered to the participating veterinarian per cat enrolled to cover these costs.


If you wish to participate, please contact Dr Jessica Quimby on 970-297-5000 or at jquimby@colostate.edu.


Metoclopramide (Reglan)

Metoclopramide is a prescription only medication which works by regulating stomach contractions. This means it can help with nausea caused by a lack of motility in the stomach. Since metoclopramide can cross the blood/brain barrier, it also acts on the brain to control feelings of nausea.


Pet Place has some information about gastric motility problems in cats (you don't need to register to read the article, just click on Close at the bottom of the pop-up window).


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, but be guided by your vet.


Metoclopramide Side Effects and Interactions

Metoclopramide may have various side effects, including constipation, hyperactivity and agitation or drowsiness; very occasionally, twitching may be seen.


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).


On 26 February 2009, the US Food and Drug Administration warned against the "chronic use of these products [metoclopramide-containing drugs] to treat gastrointestinal disorders." This is because products containing metoclopramide have 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. Obviously this warning applies to humans, but I would discuss the warning with  your vet if you want to use metoclopramide for longer than three months.


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.


Veterinary Partner has more information on metoclopramide.

Pet Place also has some information (no need to register to read the article, just click on Close at the bottom of the pop-up).

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.


Cautions                                                                                                                                              Back to Page Index

The following are not recommended for CKD cats.


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 Education has more information on Pepto-Bismol.


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. 


Back to Page Index

This page last updated: 06 December 2013

Links on this page last checked: 19 April 2012






I have tried very hard to ensure that the information provided in this website is accurate, but I am NOT a vet, just an ordinary person who has lived through CKD with three cats. This website is for educational purposes only, and is not intended to be used to diagnose or treat any cat. Before trying any of the treatments described herein, you MUST consult a qualified veterinarian and obtain professional advice on the correct regimen for your cat and his or her particular requirements; and you should only use any treatments described here with the full knowledge and approval of your vet. No responsibility can be accepted.


If your cat appears to be in pain or distress, do not waste time on the internet, contact your vet immediately.



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