TANYA'S

COMPREHENSIVE GUIDE TO

FELINE CHRONIC KIDNEY DISEASE

 

 

 

 

PHOSPHORUS BINDERS

 

ON THIS PAGE:


Why High Phosphorus Levels Matter


Methods of Control: Diet and Phosphorus Binders


When to Start Phosphorus Binders


Types of Phosphorus  Binder


Which Binder to Choose


Combining Binders


How to Give Phosphorus Binders


Monitoring


Where to Buy Phosphorus Binders


 

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Home > Key Issues > Phosphorus

 


Overview


  • If your cat's phosphorus level (in blood tests) is over 6 mg/dl (USA) or over 1.9 mmol/L (international), it is too high and you need to get it under control.

  • Keeping phosphorus levels under control should help slow the progression of the CKD, reduce the risk of serious problems (including heart problems) and make your cat feel better.

  • Feeding a food low in phosphorus is the first and best step. Ideally you want a food with a level below 0.5% phosphorus on a dry matter analysis basis. Therapeutic kidney diet foods are the only complete foods which meet this criterion.

  • If your cat will not eat a therapeutic kidney diet, feeding a food as low in phosphorus as possible and adding a phosphorus binder to the food when appropriate can help control your cat's phosphorus levels.

  • This page explains all you need to know about phosphorus binders.

  • On the left is a list of this page's contents.


Why High Phosphorus Levels Matter


 

Phosphorus is a mineral essential for good health which is contained in many foods. The body is very good at regulating its phosphorus levels by removing excess phosphorus via the kidneys. However, the kidneys of a CKD cat can no longer efficiently excrete excess phosphorus, so the vast majority of CKD cats will develop levels of phosphorus in their blood which are too high: this is known as hyperphosphataemia.

 

In contrast to the protein debate, there is no dispute about the importance of treating hyperphosphataemia because of the problems it causes. High phosphorus levels:

  • make the cat feel unwell

  • cause CKD progression

  • cause an unpleasant complication of CKD called secondary hyperparathyroidism

  • may reduce a cat's response to anaemia treatment

See The Importance of Phosphorus Control for more information on these issues.


Ways of Controlling Phosphorus Levels


 

Controlling Phosphorus Levels with Diet


The first line of phosphorus control is to feed foods low in phosphorus, ideally a therapeutic kidney diet. Survival of cats with naturally occurring chronic renal failure: effect of dietary management (2000) Elliott J, Rawlings JM, Markwell PJ, Barber PJ Journal of Small Animal Practice 41(6) pp235-242 found that feeding a reduced phosphorus therapeutic kidney diet provided effective phosphorus control in two thirds of the cats in Stage 2 and 3 CKD. In addition, the cats eating the therapeutic kidney diet lived more than twice as long as the cats in the study who ate normal food with no phosphorus binder.

 

You can read more about how to control phosphorus levels using diet on The Importance of Phosphorus Control page.

 

Controlling Phosphorus Levels with Phosphorus Binders


If your cat will not eat a therapeutic kidney diet, or if his/her phosphorus levels are still too high (over 6 mg/dl (US) or 1.9 mmol/L (international)), despite feeding such a diet for a month, products called phosphorus binders are used.  Even if your cat is eating a low phosphorus diet, at some point it is quite possible that this will become insufficient to control your cat's phosphorus levels. The role of phosphorus in feline chronic renal disease (2010) Chew D & Kidder A CVC in San Diego Proceedings states "Diet alone is not successful in adequate phosphorus control as chronic renal disease becomes more advanced. In these instances serum phosphorus concentration increases above the normal range or stays in the upper half of the normal range." In this situation, you will probably have to consider the addition of phosphorus binders.

 

Phosphorus binders work by binding with some of the phosphorus in the cat's food in the intestine, which is then passed out in the stool. This prevents the phosphorus in the food from being absorbed into the bloodstream, and therefore reduces the levels of phosphorus in the cat's body.

 

To be effective, phosphorus binders must be given shortly before or with food. You should start to see a difference in your cat's blood phosphorus levels around 7-10 days after starting binders. There are instructions on how to give binders below.

 

Using binders is not as effective as feeding a therapeutic kidney diet, because binders cannot bind all the phosphorus in the food, so your cat will still be absorbing some of the phosphorus in the food. Therefore, if you do have to feed a non-therapeutic kidney food (because the most important thing is that your cat eats), you should still aim to feed the lowest phosphorus food that your cat will eat. The Diet and Nutrition section has links to food data tables for you to check out the phosphorus levels of various cat foods. I'm not recommending any of these foods, this is simply a list in order of phosphorus content.

 

Survey of dietary and medication practices of owners of cats with chronic kidney disease (2014) Markovich JE, Freeman LM, Labato MA and Heize CR Journal of Feline Medicine and Surgery 22 found that only 22% of the 1080 cats in the survey were receiving phosphorus binders. Not all of the cats may have required binders at the time of the survey but this is still a very low percentage considering the consequences of not controlling phosphorus levels in CKD. So if your vet does not offer you phosphorus binders, do not assume you do not need them, ask for your cat's phosphorus levels and take action if your cat's levels are too high.

 


When to Start Phosphorus Binders


 

You should not normally need to use binders if your cat is eating a therapeutic kidney diet, at least in the early stages of CKD, because the therapeutic diet should be sufficient to control your cat's phosphorus levels. However, this is not always the case, particularly as the CKD worsens. The role of phosphorus in feline chronic renal disease (2010) Chew D & Kidder AC CVC in San Diego Proceedings says "Intestinal phosphate binders should be added if serum phosphate remains increased after one month of consuming the renal diet or if the switch to the renal diet is not accepted by the animal."

 

If you cannot persuade your cat to eat a therapeutic kidney diet, or if despite feeding a therapeutic kidney diet for a month, your cat's blood phosphorus levels are over 6 mg/dl (US) or 1.9 mmol/L (international), speak to your vet about adding binders.

 

If your cat isn't eating at all, there is little point giving phosphorus binders because your cat isn't ingesting any phosphorus in the food that needs binding. However, if you assist feed (as you should if your cat is not eating), you can add binders to the food you are feeding if necessary.


Types of Phosphorus Binder


 

There are five main categories of phosphorus binders based upon the primary binding ingredient:

Only three types are commonly used in cats: aluminium hydroxide, calcium carbonate and lanthanum carbonate.

Many of these products are available as simple over the counter antacids, but branded products are also available. All types have pros and cons.


Aluminium-Based Binders


 

There are three main types of aluminium-based binders, but aluminium hydroxide is generally considered to be the best choice within this family of medications.

Aluminium Magnesium Hydroxide


This type of binder, as the name suggests, also contains magnesium. Brand names include Maalox, Mylanta, Milk of Magnesia or Aludrox. Binders containing magnesium are not suitable for CKD cats because they can cause high magnesium levels in the blood, which in turn may cause urinary tract problems such as stones in some cats.

Pet Education states "Do not use magnesium containing products in animals with kidney failure."

 

Sucrose Aluminium Hydroxide


Sucrose aluminium hydroxide is also known as sucralfate or Carafate. It coats the digestive tract, so is commonly used to treat mouth ulcers or gastrointestinal bleeding.

 

One old study, Changes in serum phosphorus, calcium and alkaline phosphatase due to sucralfate (1986) Vucelić B, Hadzić N, Gragas J, Puretić Z International Journal of Clinical Pharmacology, Therapy and Toxicology 24(2) pp93-6, did find sucralfate was effective as a binder in humans.

 

Some British vets also recommend sucralfate as a phosphorus binder, but it is not a good choice for cats. Evaluating sucralfate as a phosphate binder in normal cats and cats with chronic kidney disease (2016) Quimby JM & Lappin M Journal of the American Animal Hospital Association 52(1) pp8-12 evaluated sucralfate's efficacy as a phosphorus binder in healthy cats and in CKD cats with phosphorus in the normal range. There was no change in phosphorus levels in the healthy cats, but 14.7% of them vomited after being given it. The CKD cats given sucralfate did not show reduced phosphorus levels but sixty percent (three cats out of five) exhibited vomiting, anorexia and elevated BUN and creatinine levels, to such a degree that the study was discontinued. If your vet prescribes sucralfate, I would show them this study.

 

If you are using sucralfate for mouth ulcers or gastrointestinal bleeding at the same time as using aluminium hydroxide as a phosphorus binder, you might possibly be able to reduce your dosage of aluminium hydroxide, though this is not a given based on the results of the above study.


Aluminium Hydroxide


This is the best choice of the aluminium-based binders. Its advantages are that it is effective, odourless and tasteless (if you buy the correct type), available over the counter (though you will have to use a local compounding pharmacy or mail order in the USA if you want the odourless and tasteless type) and relatively cheap.

 

See below for stockists.

Aluminium Hydroxide Formulations


Many vets are reluctant to prescribe aluminium-based binders because they think cats hate the taste. If they do prescribe them, they often prescribe AlternaGel, a peppermint-flavoured binder which most cats hate, so it then becomes a self-fulfilling prophecy. AlternaGel also contains potassium citrate, which is not a good idea because citrate can increase the absorption of aluminium within the body. 

 

Fortunately, there are alternatives. Conseal AlH are aluminium hydroxide 200 mg chews made by Bock Pharma which some vets in the USA are beginning to stock. They come in a box of 28 individually wrapped chews. The chews are semi-soft so can be broken or cut into pieces. In this form they can be mixed with food, but one member of Tanya's CKD Support Group found the chews very helpful for her cat who missed getting treats, and gave them before her cat's meals. They could also be useful for multi-cat households where you can give your CKD cat a Conseal treat whilst giving your other cats ordinary treats.

 

Alternatively, it is probably easier and certainly cheaper to buy aluminium hydroxide binders in a tasteless and odourless powder form, which most cats do not seem to notice in their food. See below for information on the various brands and where to buy them, including links to mail order suppliers who can ship to the UK, USA, Canada and Australia. Contrary to what some vets and pharmacists seem to believe, you do not need a prescription to buy these products.

 

Aluminium Hydroxide Dosage Recommendations


Unfortunately, there is no one perfect dosing schedule: it depends upon your cat's phosphorus level, stage of CKD, the type of food your cat eats and how well s/he responds to binders. Therefore there are a number of recommended dosage protocols, which fall into three categories:

  1. ISFM and Dr Chew simply give a dosage range.

  2. Dr Nagode's recommended dosage varies depending upon your cat's current phosphorus level.

  3. The IRIS recommendations look at both your cat's existing phosphorus level and your cat's creatinine level. This is because IRIS accepts that the more advanced the CKD is (as indicated by the creatinine level), the harder it can be to reduce your cat's phosphorus levels.

It is usually best to start at the lower recommended levels, increasing the dose only if your cat's blood phosphorus levels do not reduce, but be guided by your vet. See The Importance of Phosphorus Control for more on your phosphorus goals.

 

ISFM Consensus Guidelines


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 state that the starting dose is 90mg/kg per day.

 

Dr Dennis Chew of Ohio State University College of Veterinary Medicine


Dr Chew provides a helpful dosing table on page 10 of Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference. He states "initially is used at a dosage of 20-30 mg/kg q8h or 30-45 mg/kg q12h given with food." That is a total of 60-90 mg/kg a day.

Dr Larry Nagode, formerly of Ohio State University College of Veterinary Medicine


The following dosages were provided by Dr Larry Nagode, formerly of Ohio State University College of Veterinary Medicine, now sadly deceased.

 

USA

Current Phosphorus Level: mg/dl

Binder Dosage

Between 4.0 and 6.00

25 mg per lb of cat per day

Between 6.0 and 8.0

50 mg per lb of cat per day

Between 8.00 and 10.00

100 mg per lb of cat per day*

Over 10.00

Discuss with your vet

 

International

Current Phosphorus Level: µmol/L

Binder Dosage

Between 1.3 and 1.9

50 mg per kg of cat per day

Between 1.9 and 2.6

100 mg per kg of cat per day

Between 2.6 and 3.25

200 mg per kg of cat per day*

Over 3.25

Discuss with your vet

*I would not give more than 50 mg per lb of cat per day (100 mg per kg of cat per day) without detailed discussions with your vet. It is probably safe, but you need to balance the potential benefits against the possible risks, including the rare possibility of aluminium toxicity - see below. It may be safer to use a smaller amount of aluminium hydroxide together with another binder, such as lanthanum carbonate (Renalzin or Fosrenol).

The International Renal Interest Society (IRIS)


The International Renal Interest Society (2015) recommends using binders if phosphorus levels are as shown in the tables despite dietary restriction of phosphorus:

 

USA
Stage of CKD Creatinine Level (mg/dl)

Current

Phosphorus Level

Binder Dosage
IRIS Stage 2

Between 1.6 and 2.8

Above 4.6 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 3

Between 2.9 and 5.0

Above 5.0 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 4

Over 5.0

Above 6.0 mg/dl 14-28 mg per lb of cat per day

 

International

Stage of CKD

Creatinine Level (mmol/L)

Current Phosphorus Level (mmol/L)

Binder Dosage

IRIS Stage 2

Between 140 and 249

Above 1.5 30-60 mg per kg of cat per day
IRIS Stage 3

Between 250 and 439

Above 1.6 30-60 mg per kg of cat per day
IRIS Stage 4

Over 440

Above 1.9 30-60 mg per kg of cat per day

 

As you can see, the IRIS recommended amounts of binder are actually the same for every stage. What is different is:

  1. when they suggest that you try to control high phosphorus levels. For example, for a cat in IRIS Stage 2 you would treat a phosphorus level above 4.6 mg/dl or 1.5 mmol/L international, whereas, for a cat in Stage 3, a level above 4.6 mg/dl (1.6 mmol/L international) would be acceptable as long as it was no higher than 5 mg/dl (1.9 mmol/L international).

  2. the target phosphorus level for each stage of CKD. Basically you want it below the level at which you start binders, so for example, for a cat in Stage 2 you want the phosphorus level to be below 4.6 mg/dl or 1.5 mmol/L international. See The Importance of Phosphorus Control for more information on your phosphorus goals.

Aluminium Hydroxide Dosage Calculations and Adjustments


I expect your head is spinning now! I know quite a few people get confused by all these recommended dosages, so here is a summary, along with some tips on how to choose or adjust the dosage..

 

Recommendation

Cat Weight

Source

Total Daily Dosage

per kg of cat*

5 lb

2.27 kg

7.5 lbs

3.4 kg

10 lb

4.5 kg

12.5 lbs

5.7kg

IRIS 30-60 mg 68-136 mg 102-204 mg 135-270 mg 170 - 340 mg
Dr Chew 60-90 mg 136-204 mg 204-306 mg 270-405 mg 340 - 513 mg
ISFM** 90 mg 204 mg 306 mg 405 mg 513 mg
Dr Nagode 50-200 mg 113-450 mg 170-680 mg 225-900mg 285 - 1140 mg
Total Range 30-200 mg 68-450 mg 102-680 mg 135-900mg 170 - 1140 mg

*A kg is 2.2 lbs

**These are starting dosages, and can be increased if they are not sufficient to reduce your cat's blood phosphorus levels

Remember, the amounts given are the total daily dosage. The total amount should be divided among as many of your cat's daily meals as possible, ideally with larger meals receiving a larger proportion of the daily dose (see Mixing with Food below).

 

See below for how to give binders, including how to mix them with your cat's food.

Aluminium Hydroxide: Choosing a Dosage


The ranges for how much to give are quite wide, so talk to your vet about a suitable starting point for your cat. Many people successfully follow Dr Nagode's recommendations above, though these tend to be higher than those of other experts, because recently there is a trend to be more cautious with dosing in order to reduce the risk of aluminium toxicity.

 

Taking all the experts' recommendations above, here is what I would probably try myself. However, this is just my opinion, and if your vet recommends a different dosage regimen, you should of course follow your vet's advice:

 

Cat's Phosphorus Level mg/dl Cat's Phosphorus Level µmol/L Possible Starting Daily Dose
Below 6 Below 1.9

30 mg per kg of cat

14 mg per lb of cat

Between 6 and 7 Between 1.9 and 2.25

60 mg per kg of cat

27 mg per lb of cat

Above 7 Above 2.25

90 mg per kg of cat

40 mg per lb of cat

 

Aluminium Hydroxide: Adjusting a Dosage


Your cat's blood phosphorus levels should start falling 7-10 days after starting a phosphorus binder. Your vet should check your cat's blood phosphorus levels 10-14 days after starting a binder. If your cat's blood phosphorus level is not falling, you should discuss increasing the dose you are using with your vet. If the phosphorus level seems to be falling, I would continue with the dosage you are using.

 

I am often asked if you should stop using a binder or adjust the dosage once your cat's blood phosphorus has fallen to a satisfactory level. Normally you will need to continue with the binder. In most cases, you will need to continue with the dosage that reduced your cat's blood phosphorus levels to your target level, but you can of course speak to your vet about adjusting the dose, either upwards or downwards, if necessary, e.g. if your cat's CKD starts to worsen and phosphorus levels start to rise again.

 

See Monitoring Phosphorus Levels for more information.

 

Measuring Aluminium Hydroxide 


Aluminium hydroxide does not have to be measured too precisely, but as a rough guide:

 
Form of Aluminium Hydroxide Quantity Contains approximately
Powdered Quarter of a teaspoon (1/4 tsp, ¼ tsp), loosely packed 300 mg of aluminium hydroxide
Liquid e.g. AlternaGel One teaspoon 600mg of aluminium hydroxide

 

I used to have this table on the website, and have received so many requests for it that I am including it again. Please note that the amounts involved are so tiny that I have had to do quite a bit of rounding up or down.

  Cat Weight

Source

Total Daily Dosage

per kg

5 lb

2.27 kg

7.5 lbs

3.4 kg

10 lb

4.5 kg

12.5 lbs

5.7kg

   

Dosage

mg

Dosage tsp Dosage mg Dosage tsp Dosage mg Dosage tsp Dosage mg Dosage tsp
IRIS 30-60 mg 68-135 1/16-1/9 102-204 1/12-1/6 135-270 1/8-1/4 170-340 1/8-1/4
Dr Chew 60-90 mg 135-204 1/9-1/6 204-306 1/6-1/4 270-405 1/4-1/3 340-513 1/4-2/5
ISFM* 90 204 1/6 306 1/4 405 1/3 513 2/5
Dr Nagode** 50-200 mg 113-450 1/9-3/8 170-680 1/8-1/2 225-900 1/6-3/4 285-1140 1/4-1.0
Total Range 30-200 mg 68-450 1/16-3/8 102-680 1/12-1/2 135-900 1/8-3/4 170-1140 3/4-1.0

* Starting dose

** Dr Nagode's recommendations vary depending upon the cat's initial blood phosphorus level

 

Yep, these numbers are tiny and fiddly. I recommend that rather than guessing and trying to measure tiny quantities, you buy a set of measuring spoons which include a pinch (I think this may be 1/16th), 1/8, 1/4, 1/2, 2/3 and 1 tsp for less than USD9 from Amazon. The same set costs £25.78 (spot the ripoff) from Amazon UK. If you buy these, you can simply scoop out the amount you need each day using the appropriate spoon.

 

If you can't get the spoons and need to measure it yourself, try this:

  • take a standard-sized teaspoon (the standard-sized teaspoon typically holds 5ml of liquid).

  • Fill your teaspoon with aluminium hydroxide powder.

  • Then empty onto a dish and divide it as needed. For example, if you are giving a quarter of a teaspoon (¼ of a tsp) a day, divide your pile into four. You would then have four days worth of aluminium hydroxide treatment on your dish.

  • If you look at the numbers above, you can see how many piles to divide into. So for three eighths, divide it into eight and you would use three of the eight portions. For one sixth, divide into six and use one portion per day; and so on.

  • Remember, you won't give your daily dosage all in go. You will divide it between your cat's meals.

How to Give Aluminium Hydroxide: Mixing Binders with Food


Phosphorus binders must be given with food so they can bind with the phosphorus in it. Aluminium hydroxide binders are usually odourless and tasteless if you choose carefully, but since they are a natural (mined) product, they can sometimes add a bit of a gritty texture to food or make it taste a little drier.

 

People used to be confused that the dosage of phosphorus binder recommended did not take into account the size of the meal being consumed. Specialists such as Dr Chew in Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference are now advising that "The dose of any phosphate binder should be based on the meal size (phosphorus intake) and the prevailing serum phosphorus level for each CKD patient; the dose is titrated to effect." Obviously this is the ideal, so if you know, for example, that your cat always eats larger meals in the evening than in the morning, you can adjust the dose accordingly.

Giving Binders with Canned Food


  • tablets can simply be crushed and added to the food.

  • capsules can be opened and the contents mixed with the food (after measuring as above).

  • liquid binders can either be mixed in the food or syringed into your cat's mouth just before eating.

  • one retailer recommends adding a teaspoon of water to the tinned food and binder and letting it stand for ten minutes before serving in order to let the binder mix thoroughly. This may help remove any grittiness.

 

Giving Binders with Dry Food


  • try putting the food in a freezer bag together with the crushed or powder binder and leave them to mingle overnight.

  • if you are using a liquid binder, you can syringe it into your cat's mouth just before eating.

Aluminium Hydroxide Side Effects


Sometimes aluminium hydroxide-based binders may cause constipation, so watch for this when you first start them and be ready to start a suitable treatment if required.

 

Please see below for more information on aluminium toxicity.

 

Aluminium Hydroxide Interactions


 

Potassium Citrate


As Drugs mentions, products containing citrate may increase the absorption of aluminium, which could increase the risk of aluminium toxicity (though apparently these findings have not been replicated in cats). The most commonly used citrate-containing products in CKD cats are potassium citrate (perhaps to treat metabolic acidosis), and many therapeutic kidney diets.

 

If you are using potassium citrate, give this at least two hours apart from aluminium-based binders.

 

It is trickier to juggle aluminium hydroxide and therapeutic kidney diets because binders of course need to be given with food. You will probably not need to use phosphorus binders if you are using a therapeutic kidney diet, at least in early to mid stage CKD, but if you do have to use both, check the therapeutic kidney food you are feeding to see if it contains potassium citrate (other forms of potassium are not a problem) and consider switching to another therapeutic kidney food which does not contain potassium citrate. It might also be worth switching to another type of phosphorus binder, either completely or by mixing aluminium hydroxide with foods not containing potassium citrate and adding another binder to foods which do contain potassium citrate. Speak to your vet about the best way forward.

 

Other Interactions


In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew says "Due to varying effects of intestinal phosphate binders to limit absorption of drugs, it is advisable to give other drugs 1 hour before or 3 hours after any intestinal phosphate binder is given."

 

The following specific interactions are noted:

  • According to Plumb's Veterinary Drug Handbook, aluminium hydroxide should be given two hours apart from Baytril, an antibiotic. It is probably wise to keep aluminium hydroxide away from antibiotics generally, particularly those in the same family as Baytril (this includes Zeniquin).

  • Aluminium hydroxide should ideally be given separately from iron, because the aluminium hydroxide may reduce the absorption of the iron.

  • Plumb's Veterinary Drug Handbook also advises giving aluminium hydroxide two hours apart from famotidine (Pepcid AC), which is used to treat excess stomach acid, because it may interfere with the absorption of the treatment, which would make it less effective. However, 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." 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.

  • Aluminium hydroxide binders should be given two hours apart from ACE inhibitors, because the binder may reduce the bioavailability of the ACE inhibitors. Drugs has more information about this.

  • Medline Plus mentions that vitamin C may interact adversely with products containing aluminium, such as phosphorus binders. Cats do not need Vitamin C supplements anyway, they can manufacture all the Vitamin C they need themselves.

  • I don't know if slippery elm bark would interfere with aluminium hydroxide, as far as I know this has never been studied, but it might be possible in theory. However, if you are adding Slippery Elm Bark to food once or twice a day, I would still mix binders in with that food in the hope that at least some of the phosphorus would be bound.

Aluminium Toxicity


You may have read that there is a risk of aluminium toxicity from the aluminium in aluminium hydroxide medications. This applies in particular to human patients on dialysis, because aluminium is used in the dialysis process. Do aluminium hydroxide binders continue to have a role in contemporary nephrology practice? (2011) Mudge DW, Johnson DW, Hawlet CM, Campbell SB, Isbel NM, van Eps CL & Petrie JJB Nephrology 12 states "Available historical evidence however, suggests that neurological toxicity may have primarily been caused by excessive exposure to aluminium in dialysis fluid, rather than aluminium-containing oral phosphate binders. Limited evidence suggests that aluminium bone disease may also be on the decline in the era of aluminium removal from dialysis fluid, even with continued use of aluminium binders...The relative contribution of aluminium binders to aluminium toxicity would appear to be minor based on the available evidence." Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels? (2011) Pepper R, Campbell N, Yaqoob MM, Roberts NB & Fan SLS BMC Nephrology 12 found that even patients on dialysis did not develop aluminium toxicity if changes were made to the dialysis process (during which patients may be exposed to dialysate water which is contaminated with aluminium), but the patients in this study were on relatively low doses of aluminium hydroxide.

Since cats are not on dialysis, aluminium toxicity was not thought to be a concern for cats (or dogs), especially since even in humans it takes years before it becomes a problem, and cats and dogs don't live as long as humans. Recently, however, there has been increasing concern about the possible risk of aluminium toxicity in cats using aluminium hydroxide based binders. This is partly because of a study which reported on aluminium toxicity in two dogs on binders, Aluminum toxicity following administration of aluminum-based phosphate binders in 2 dogs with renal failure (2008) Segev G, Bandt C, Francey T & Cowgill LD Journal of Veterinary Internal Medicine 22(6) pp1432-5. There is no abstract available for this study, but Treatment options for hyperphosphataemia in feline CKD: what's out there? (2009) Kidder AC & Chew D Journal of Feline Medicine & Surgery 11(11) pp813-24 reported that the two dogs in question developed "probable aluminum toxicity" after being on binders for only 62 and 65 days. The symptoms seen were "severe neuromuscular abnormalities." The dogs were on dosages of 125mg/kg per day (or 56mg per lb body weight) and 200 mg/kg (or 91mg per lb bodyweight) per day, which are not particularly high doses. However, both these dogs had been on dialysis, though apparently the dialysate water was not contaminated with aluminium.

 

Partly because of this study, vets are becoming increasingly aware of the need for caution and awareness when using aluminium hydroxide binders in cats too, particularly when using large doses. In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference, Dr D Chew says "THERE IS NO KNOWN SAFE DOSE OF ALUMINUM SALTS FOR HUMANS WITH CKD. Detrimental effects of aluminum based phosphate binders as described in humans seen in humans have not been systematically evaluated in small animal patients and are rarely clinically appreciated. As cats with CKD can live for years on treatment, concerns for aluminum accumulation deserve more study as to long-term safety."

Physical symptoms to watch for include muscle weakness or neurological problems, such as stumbling and an awkward gait (although, just to complicate matters, these can actually be signs of uncontrolled phosphorus levels too, see above). One possible early sign of aluminium toxicity is a change in MCV. This is a measure of red blood cell size. If your cat has a low MCV (known as microcytosis), this means the red blood cells are smaller than usual. Although this may simply indicate iron deficiency, it may also be a sign of aluminium toxicity. This sign normally appears before you see physical symptoms, so be sure to monitor your cat's MCV levels.

If you are using potassium citrate (perhaps to treat metabolic acidosis), give this at least two hours apart from phosphorus binders. This is because, as Drugs explains, products containing citrate can in theory increase the absorption of aluminium, which could increase the risk of aluminium toxicity. Many therapeutic kidney diets contain potassium citrate. See above for more information on aluminium hydroxide and potassium citrate.

 

Try not to worry too much. I am only aware of one case of aluminium hydroxide toxicity in cats to date (this cat was given massive doses of aluminium hydroxide, more than twice as much as she would normally be given based upon Dr Nagode's table above), and most cases in dogs have occurred in dogs taking over 200 mg/kg. In Updates in feline chronic kidney disease (2008) Dr CL Langston states "Excessive absorption of aluminum can lead to toxicity, including anemia and neurologic symptoms, but this seems uncommon in veterinary practice." In contrast, the dangers of elevated phosphorus control are very real, and very common, and controlling phosphorus is essential for your cat's wellbeing.

 

If your cat has phosphorus levels that require large amounts of aluminium hydroxide, or if you cannot control your cat's phosphorus levels with aluminium hydroxide only, consider adding another phosphorus binder. Most people in this situation use lanthanum carbonate (Renalzin or Fosrenol)See below for suggestions on dosage.

 

If you think your cat may have aluminium toxicity, I would ask for a referral to a vet school or a neurologist if possible. Chelation therapy plus dialysis helped to remove the aluminium from dogs with aluminium toxicity, and indeed following treatment the neurological problems experienced by the dogs in the above study were successfully reversed.

 

Aluminium Hydroxide: Other Concerns


If you buy aluminium hydroxide gel or powder in the USA, you may see a warning about arsenic which bizarrely supposedly only applies to people living in California. This is to comply with that state's legal requirements. The fact of the matter is that aluminium hydroxide is a naturally occurring product which is mined, and therefore it contains a naturally occurring tiny amount of arsenic of no more than 8 parts per million. This is no more than you might find in soil or in vegetables grown in soil. However, if you want to be on the safe side, you might wish to avoid inhaling the powder.

If you buy aluminium hydroxide, you may see an expiration date on it. This is usually to comply with pharmacy laws, but in practice, since aluminium hydroxide is a mineral that is mined from the earth, it cannot really expire, so if you are using a gel or powder form of aluminium hydroxide, I would not worry too much about expiry dates. However, if you are using a suspension of some kind, it may expire because of other ingredients in the mix.

 


Lanthanum Carbonate


Lanthanum carbonate is a newer type of phosphorus binder. Like aluminium hydroxide, it appears to be tasteless and Pharmacology of the phosphate binder, lanthanum carbonate (2011) Damment SJP Renal Failure 33(2) pp217–224 found that lanthanum carbonate-based binders appear to be as effective as aluminium hydroxide-based binders.

 

Multicenter prospective randomized, double-blind comparative study between lanthanum carbonate and calcium carbonate as phosphate binders in Japanese hemodialysis patients with hyperphosphatemia (2008) Shigematsu T Clinical Nephrology 70(5) pp404-10 found lanthanum carbonate and calcium carbonate had similar levels of efficacy in lowering phosphorus levels, but lanthanum carbonate was better at lowering the incidence of elevated calcium levels.

 

Lanthanum Carbonate-based Formulations


The two most commonly used forms of lanthanum are Fosrenol and Renalzin. Renalzin is designed for cats but sadly has been discontinued so is very hard to find. Fosrenol is a human medication.

 

Renalzin


In October 2008 a binder containing lanthanum carbonate known as Renalzin was released in Europe for the feline market. Sadly, in late 2014 the manufacturer, Bayer, announced that Renalzin was to be discontinued and it is now (2016) extremely hard to find and will probably disappear completely by the end of the year.

 

Renalzin contains Vitamin E and kaolin as well as lanthanum carbonate. The vitamin E is intended to act as an antioxidant, and the kaolin as a "toxin binder", by which I think they mean an oral adsorbent. Kaolin (which is often used to treat diarrhoea) can be constipating, so it seems an unusual choice of ingredient, but I suspect Bayer were jumping on the Ipakitine/Epakitin bandwagon here by wanting to add an oral adsorbent.

 

Renalzin also contains the preservative Methyl 4-hydroxybenzoate (E218). According to the UK Food Guide, this additive is banned in Australia and France. A German site, the Lebensmittel-Lexikon (Food Lexicon), says that it has a high allergic potential and may cause asthma attacks.

 

Safety and efficacy of Lantharenol (Lanthanum carbonate octahydrate) as a feed additive for cats according to Regulation (EC)  No 1831/2003 is a European Food Safety Authority report on the basis on which Renalzin was approved. This refers to a number of supporting studies but the majority of these have not been published yet.

Fosrenol


As stated above, Renalzin, the feline version of lanthanum carbonate, has been discontinued. Renalan, another lanthanum-based phosphorus binder, was undergoing testing on cats and was reported to be seeking regulatory approval in 2008 but it seems to have disappeared. Therefore your only choice once Renalzin is no longer available will be Fosrenol.

 

Fosrenol is the human version of lanthanum carbonate which has been available in the USA since 2005 and is gradually being used in cats. A prescription is required. Fosrenol comes in the form of extremely expensive tablets which are supposed to be chewed, but in order to use them for cats, most people crush the tablets. In 2015 a powder form was released. In humans this is supposed to be mixed with apple sauce or similar but I imagine you could simply add it to your cat's food.

See below for stockists.

Fosrenol - the manufacturer's (Shire's) website.

Eurek Alert has a press release regarding the approval process for Fosrenol in the USA.

 

Lanthanum Carbonate Dosage Recommendations


Fosrenol dosing is the same as for aluminium hydroxide. So, for example, if you are giving 300mg of aluminium hydroxide a day but want to switch to Fosrenol, you would still need to give 300mg per day. Having said that, there are a number of recommended dosage protocols, as follows:

 

ISFM Consensus Guidelines


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 state that the starting dose is 30-90mg/kg per day.

 

Dr Dennis Chew of Ohio State University College of Veterinary Medicine


Dr Chew provides a helpful dosing table on page 10 of Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference. He states "doses of 35 mg/kg/day to 50 mg/kg/day are often needed since commercial cat foods contain more phosphate proportionally than what an average human consumes daily. A recent abstract in a small number of CKD cats administered lanthanum carbonate in food at 95 mg/kg/day to achieve very modest serum phosphate control (Pressler ACVIM 2013)."

 

The International Renal Interest Society


The International Renal Interest Society (2015) recommends a staged approach to phosphorus control, as shown in the tables below. It recommends using binders if phosphorus levels are as shown in the tables despite dietary restriction of phosphorus.

 

USA
Stage of CKD Creatinine Level (mg/dl)

Current

Phosphorus Level

Binder Dosage
IRIS Stage 2

Between 1.6 and 2.8

Above 4.6 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 3

Between 2.9 and 5.0

Above 5.0 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 4

Over 5.0

Above 6.0 mg/dl 14-28 mg per lb of cat per day

 

International

Stage of CKD

Creatinine Level (mmol/L)

Current Phosphorus Level (mmol/L)

Binder Dosage

IRIS Stage 2

Between 140 and 249

Above 1.5 30-60 mg per kg of cat per day
IRIS Stage 3

Between 250 and 439

Above 1.6 30-60 mg per kg of cat per day
IRIS Stage 4

Over 440

Above 1.9 30-60 mg per kg of cat per day

 

As you can see, the recommended amounts of binder are actually the same for each stage. What is different is:

  • firstly, when you start treating for high phosphorus levels. For example, for a cat in IRIS Stage 2 you would start treating a phosphorus level above 4.6 mg/dl or 1.5 mmol/L international, whereas for a cat in Stage 3 a level above 4.6 mg/dl (1.6 mmol/L international) would be acceptable as long as it was no higher than 5 mg/dl (1.9 mmol/L international).

  • secondly, the target phosphorus level for each stage of CKD. Basically you want it below the level at which you start binders, so for example, for a cat in Stage 2 you want the phosphorus level below 4.6 mg/dl or 1.5 mmol/L international. See The Importance of Phosphorus Control for more information on your phosphorus goals.

See below for how to give lanthanum.

 

Renalzin Dosage


Renalzin is supplied in pump form and one dose provides 1 ml, which contains 200mg of lanthanum carbonate. Bayer recommends that two pumps (2ml) a day are used for dry food, giving a total dose of 400mg of lanthanum carbonate each day. For canned food, it recommends three pumps a day (3ml), giving a total dose of 600mg of lanthanum carbonate each day,

 

Compared with the recommended human starting dose for Fosrenol (which also contains lanthanum carbonate) of 750-1500mg a day, this seems relatively high. However, veterinary sources have stated that lanthanum carbonate can be dosed in the same way as aluminium hydroxide, in which case 400mg is within normal levels for a 10 lb cat, but 600mg seems quite high. You can see a summary of the recommended lanthanum carbonate dosages below.

It is not essential to give Renalzin only twice a day, the total daily dose can be calculated and spread over all meals. Phosphorus levels should be checked after 2-4 weeks and the dose adjusted as required. Like Ipakitine/Epakitin, Renalzin is supposed to be given for up to six months only, but most CKD cats have an ongoing requirement for phosphorus control.

Lanthanum Carbonate Dosage Calculations and Adjustments


I expect your head is spinning now! I know quite a few people get confused by all these recommended dosages, so here is a summary:

Recommendation

Cat Weight

Source

Total Daily Dosage

per kg of cat*

5 lb

2.27 kg

7.5 lbs

3.4 kg

10 lb

4.5 kg

12.5 lbs

5.7kg

IRIS 30-60 mg 68-136 mg 102-204 mg 135-270 mg 170-340 mg
Dr Chew 35-50 mg 80-114 mg 119-170mg 158-225 mg 200-285 mg
ISFM** 30-90 mg 68-204 mg 102-306 mg 135-405mg 170-513 mg
Renalzin 400 mg per cat per day 400 mg 400 mg 400 mg 400 mg
Total Range 30-90 mg 68-204 mg 102-306 mg 135-405mg 170-513 mg

*A kg is 2.2 lbs

**These are starting dosages, and can be increased if they are not sufficient to reduce your cat's blood phosphorus levels

Remember, the amounts given are the total daily dosage. The total amount should be divided among as many of your cat's daily meals as possible, ideally with larger meals receiving a larger proportion of the daily dose (see Mixing with Food below).

 

See below for how to give binders, including how to mix them with your cat's food.

It is usually best to start at the lower recommended levels, increasing the dose only if your cat's blood phosphorus levels do not reduce, but be guided by your vet. See The Importance of Phosphorus Control for more on your phosphorus goals.

Lanthanum Carbonate: Choosing a Dosage


The ranges for how much to give are quite wide, so talk to your vet about a suitable starting point for your cat.

 

Taking all the experts' recommendations above, here is what I would probably try myself. However, this is just my opinion, and if your vet recommends a different dosage regimen, you should of course follow your vet's advice:

 

Cat's Phosphorus Level mg/dl Cat's Phosphorus Level µmol/L Possible Starting Daily Dose
Below 6 Below 1.9

30 mg per kg of cat

14 mg per lb of cat

Between 6 and 7 Between 1.9 and 2.25

60 mg per kg of cat

27 mg per lb of cat

Above 7 Above 2.25

90 mg per kg of cat

40 mg per lb of cat

 

Lanthanum Carbonate: Adjusting a Dosage


Your cat's blood phosphorus levels should start falling 7-10 days after starting a phosphorus binder. Your vet should check your cat's blood phosphorus levels 10-14 days after starting a binder. If your cat's blood phosphorus level is not falling, you should discuss increasing the dose you are using with your vet. If the phosphorus level seems to be falling, I would continue with the dosage you are using.

 

I am often asked if you should stop using a binder or adjust the dosage once your cat's blood phosphorus has fallen to a satisfactory level. Normally you will need to continue with the binder. In most cases, you will need to continue with the dosage that reduces your cat's blood phosphorus levels to your target level, but you can of course speak to your vet about adjusting the dose, either upwards or downwards, if necessary, e.g. if your cat's CKD starts to worsen and phosphorus levels start to rise again.

 

See Monitoring Phosphorus Levels for more information.

 

How to Give Lanthanum Carbonate: Mixing Binders with Food


Phosphorus binders must be given with food so they can bind with the phosphorus in it.

 

People used to be confused that the dosage of phosphorus binder recommended did not take into account the size of the meal being consumed. Specialists such as Dr Chew in Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference are now advising that "The dose of any phosphate binder should be based on the meal size (phosphorus intake) and the prevailing serum phosphorus level for each CKD patient; the dose is titrated to effect." Obviously this is the ideal, so if you know, for example, that your cat always eats larger meals in the evening than in the morning, you can adjust the dose accordingly.

Giving Binders with Canned Food


  • Fosrenol tablets can simply be crushed and added to the food in appropriate amounts.

  • Renalzin can be sprayed directly onto food. The product on sale in Germany says that three pumps (3ml) a day should be mixed with canned food. I have no idea what you are supposed to do if you are feeding both dry and canned, presumably average it out. Renalzin is supposed to be odourless and tasteless and many members of Tanya's CKD Support Group find their cats accept it happily in their food (apparently it makes canned food quite creamy), but one user in Germany has reported that it tasted slightly bitter and mouldy to her.

Giving Binders with Dry Food


  • Fosrenol tablets can simply be crushed and added to the food in appropriate amounts. Try putting the food in a freezer bag together with the crushed binder and leave them to mingle overnight.

  • Renalzin can be sprayed directly onto food. The product on sale in Germany says that two pumps (2ml) a day should be mixed with dry food. I have no idea what you are supposed to do if you are feeding both dry and canned, presumably average it out. Renalzin is supposed to be odourless and tasteless and many members of Tanya's CKD Support Group find their cats accept it happily in their food (which it makes quite creamy), but one user in Germany has reported that it tasted slightly bitter and mouldy to her.

Lanthanum Carbonate-based Binders Side Effects


The most common side effects for humans taking lanthanum carbonate are nausea, vomiting and diarrhoea, and I have also heard of CKD cats who developed nausea and vomiting whilst taking Renalzin. The manufacturer confirmed to one person's vet that these were possible side effects.

 

In September 2011 an Important Drug Warning was issued warning of a risk of faecal impaction when using Fosrenol. The warning advises caution for patients who are constipated, diabetic or using a calcium channel blocker (such as amlodipine, used to treat high blood pressure in CKD cats).

Effects of phosphorus binders in moderate CKD (2012) Block GA, Wheeler DC, Persky MS, Kestenbaum B, Ketteler M, Spiegel DM, Allison MA, Asplin J, Smits G, Hoofnagle AN, Kooienga L, Thadhani R, Mannstadt M, Wolf M & Chertow GM Journal of the American Society of Nephrology 23(8) pp1407-15 found that binders containing lanthanum carbonate did reduce phosphorus levels but also caused calcium build up in blood vessels, which can lead to heart problems.

 

Lanthanum Carbonate-based Binders Interactions


In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew says "Due to varying effects of intestinal phosphate binders to limit absorption of drugs, it is advisable to give other drugs 1 hour before or 3 hours after any intestinal phosphate binder is given."

 

Plumbs Veterinary Drugs Handbook says "Drug interactions with lanthanum carbonate have not been reported, but as it is a binding agent similar to aluminum, it seems prudent to separate by two hours dosing lanthanum and the following:"

  • Baytril, an antibiotic. Renalzin is not absorbed into the digestive tract like aluminium hydroxide-based binders, and therefore should have fewer possible interactions with other treatments. Nevertheless, Bayer recommends that it should be separated from any other medications by 1-3 hours, particularly benazepril. Please see below for more on possible interactions.  It is probably wise to keep lanthanum carbonate away from antibiotics generally, particularly those in the same family as Baytril (this includes Zeniquin).

  • iron, because lanthanum carbonate may reduce absorption of iron.

I don't know if slippery elm bark would interfere with lanthanum carbonate, as far as I know this has never been studied, but it might be possible in theory. However, if you are adding Slippery Elm Bark to food once or twice a day, I would still mix binders in with that food in the hope that at least some of the phosphorus would be bound.


Calcium-Based Binders


 

Sometimes your vet will recommend using a calcium-based antacid as a phosphorus binder. Over the counter products, such as Tums or PhosLo, are widely available and cheap but many vets also sell commercial products made for cats, all of which have additional ingredients and cost a lot more. See below for stockists.

 

Calcium Acetate


The calcium acetates (e.g. PhosLo) bind 2-3 times as much phosphorus as calcium carbonate (e.g. Tums). On the other hand, they are more likely to cause elevated calcium levels in the blood (hypercalcaemia). They also do not bind as much phosphorus as aluminium hydroxide or lanthanum carbonate binders.

 

Calcium Acetate Dosage Recommendations


 

ISFM Consensus Guidelines


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 state that the starting dose is 60-90mg/kg per day.

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 270-405mg of binder a day, spread over the cat's meals.

Dr Dennis Chew of Ohio State University College of Veterinary Medicine


In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew states "can be used at a starting dosage of 30-mg/kg q8h or 45-mg/kg q12h given with food."

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 135-200mg of binder three times a day or 202mg of binder twice a day, resulting in a daily total of 405mg of binder.

The International Renal Interest Society (IRIS)


The International Renal Interest Society (2015) recommends using binders if phosphorus levels are as shown in the tables despite dietary restriction of phosphorus:

USA
Stage of CKD Creatinine Level (mg/dl)

Current

Phosphorus Level

Binder Dosage
IRIS Stage 2

Between 1.6 and 2.8

Above 4.6 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 3

Between 2.9 and 5.0

Above 5.0 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 4

Over 5.0

Above 6.0 mg/dl 14-28 mg per lb of cat per day

 

International

Stage of CKD

Creatinine Level (mmol/L)

Current Phosphorus Level (mmol/L)

Binder Dosage

IRIS Stage 2

Between 140 and 249

Above 1.5 30-60 mg per kg of cat per day
IRIS Stage 3

Between 250 and 439

Above 1.6 30-60 mg per kg of cat per day
IRIS Stage 4

Over 440

Above 1.9 30-60 mg per kg of cat per day

 

As you can see, the recommended amounts of binder are actually the same for each stage. What is different is:

  • firstly, when you start treating for high phosphorus levels. For example, for a cat in IRIS Stage 2 you would start treating a phosphorus level above 4.6 mg/dl or 1.5 mmol/L international, whereas for a cat in Stage 3 a level above 4.6 mg/dl (1.6 mmol/L international) would be acceptable as long as it was no higher than 5 mg/dl (1.9 mmol/L international).

  • secondly, the target phosphorus level for each stage of CKD. Basically you want it below the level at which you start binders, so for example, for a cat in Stage 2 you want the phosphorus level below 4.6 mg/dl or 1.5 mmol/L international. See The Importance of Phosphorus Control for more information on your phosphorus goals.

Calcium Carbonate


You can buy calcium carbonate-based binders over the counter  - Tums is a widely available product of this type. The risk of hypercalcaemia is lower with calcium carbonate-based binders than with calcium acetate-based, though it still exists. These products only bind a third to a half of the phosphorus that calcium acetate-based binders bind, and a lot less than aluminium hydroxide or lanthanum carbonate.

 

A number of manufacturers now make calcium carbonate-based products for cats, most of which have additional ingredients, as follows:

Calcium Carbonate Dosage Recommendations


These are the recommended dosages for over the counter calcium carbonate products. If you are using one of the branded products discussed below, follow the manufacturer's recommendations after discussion with your vet.

 

ISFM Consensus Guidelines


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 state that the starting dose is 90mg/kg per day.

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 405mg of binder a day, spread over the cat's meals.

Dr Dennis Chew of Ohio State University College of Veterinary Medicine


In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew states "can be used at a starting dosage of 30-mg/kg q8h or 45-mg/kg q12h given with food."

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 135-200mg of binder three times a day or 202mg of binder twice a day, resulting in a daily total of 405mg of binder.

The International Renal Interest Society (IRIS)


The International Renal Interest Society (2015) recommends using binders if phosphorus levels are as shown in the tables despite dietary restriction of phosphorus:

 

USA
Stage of CKD Creatinine Level (mg/dl)

Current

Phosphorus Level

Binder Dosage
IRIS Stage 2

Between 1.6 and 2.8

Above 4.6 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 3

Between 2.9 and 5.0

Above 5.0 mg/dl 14-28 mg per lb of cat per day
IRIS Stage 4

Over 5.0

Above 6.0 mg/dl 14-28 mg per lb of cat per day

 

International

Stage of CKD

Creatinine Level (mmol/L)

Current Phosphorus Level (mmol/L)

Binder Dosage

IRIS Stage 2

Between 140 and 249

Above 1.5 30-60 mg per kg of cat per day
IRIS Stage 3

Between 250 and 439

Above 1.6 30-60 mg per kg of cat per day
IRIS Stage 4

Over 440

Above 1.9 30-60 mg per kg of cat per day

 

As you can see, the recommended amounts of binder are actually the same for each stage. What is different is:

  • firstly, when you start treating for high phosphorus levels. For example, for a cat in IRIS Stage 2 you would start treating a phosphorus level above 4.6 mg/dl or 1.5 mmol/L international, whereas for a cat in Stage 3 a level above 4.6 mg/dl (1.6 mmol/L international) would be acceptable as long as it was no higher than 5 mg/dl (1.9 mmol/L international).

  • secondly, the target phosphorus level for each stage of CKD. Basically you want it below the level at which you start binders, so for example, for a cat in Stage 2 you want the phosphorus level below 4.6 mg/dl or 1.5 mmol/L international. See The Importance of Phosphorus Control for more information on your phosphorus goals.

 

Ipakitine/Epakitin


Ipakitine (known as Epakitin in the USA and Canada) is a combination of a calcium carbonate-based phosphorus binder and chitosan. In Renal disease in cats (2013) Crieff 2 Day Small Animal CPD Meeting pp125-144 Prof D Gunn-Moore says that chitosan is combined with calcium carbonate "to reduce phosphate absorption from the intestines." Some people believe chitosan may also act as an oral adsorbent and help bind with uraemic toxins, thus improving wellbeing. There is more information about Ipakitine, including its adsorbent properties, on the Treatments page.

In the marketing literature, emphasis seems to be placed on Ipakitine's role as a phosphorus binder, but many vets seem to sell it to clients whose cats do not have elevated phosphorus levels, so they are presumably advocating it for its chitosan-related effects on uraemic toxins. It is only supposed to be given for six months, but I have heard of cats who have been on it for longer with no obvious problems. The manufacturer has stated it should be OK to give it for longer for six months under veterinary supervision.

I have not been able to find out exactly how much calcium carbonate is in Ipakitine in the UK or Epakitin in the USA. Drugs states that 1g of the Canadian version of Epakitin contains 100mg of calcium carbonate and 80mg of chitosan, and I presume the US and European versions are similar. The recommended dose is 1g of Epakitin per 5kg (11 lb) of cat given twice a day with meals, which equates to 200mg of calcium carbonate per day for an 11 lb (5kg) cat. This is within typical veterinary guidelines for calcium carbonate dosages, see below.

 

According to the manufacturer, Ipakitine contains a high (70-90) percentage of lactose, so I would not use it if your cat is lactose intolerant.

 

Effects of an intestinal phosphorus binder on serum phosphorus and parathyroid hormone concentration in cats with reduced renal function (2008) Brown SA, Rickertson M & Sheldon S International Journal of Applied Research in Veterinary Medicine 6(3) pp155-160 reports on a small randomised placebo-controlled study (partly funded by the manufacturers) of twelve cats without naturally occurring kidney disease, which indicated that Epakitin appeared to reduce phosphorus levels in the cats, who were fed a commercial (non-prescription) diet and who were in IRIS Stages 1 and 2.

 

See below for stockists.

 

Renal (by Candioli) or Aventi KP


Renal is made by Candioli Pharma in Italy and is commonly offered to people in Italy, and occasionally to people in other parts of Europe.

 

Aventi KP is the same product, and is commonly offered to people in Canada, where it is marketed by Aventix Animal Health. Drugs has some information about it.

 

Like Ipakitine, this product contains calcium carbonate and chitosan, but it also contains potassium citrate and fructooligosaccharides (FOS). Since not every CKD cat needs these additional ingredients, I think I would give this product a miss.

 

Renaltan


Renaltan is a liquid calcium carbonate-based phosphorus binder made by Recoactiv (RecoVet) in Germany. It also contains some B vitamins, essential fatty acids and minerals. The manufacturer's website does not specify the precise amounts of any of the ingredients, so I do not know how much calcium carbonate it contains, or how much of anything else, come to that.

 

The manufacturer claims that this product stimulates the appetite and increases food intake, which I presume is because of the B vitamins. It also claims that by using this product, you can avoid using prescription food in IRIS Stages 1 and 2 because you are controlling phosphorus levels but leaving protein levels untouched. Whilst it is true that it is not necessarily a good idea to reduce protein levels in IRIS Stages 1 and 2 (see Nutritional Requirements), prescription foods do have other attributes (see Which Foods to Feed for information on when and why to use prescription food).

 

I have heard from a few German users who seem to like Renaltan. It is available from the manufacturer's own website (first link above), from Tiernaturprodukte or from Amazon Germany. Since I don't know the precise composition of this product, I would not use it.

 

Pronefra


Pronefra, made by Virbac, is a new phosphorus binder launched in 2014. It is marketed as a "supplementary food" and contains four main ingredients:

  • calcium carbonate (3.57%) and magnesium carbonate (0.95%) as phosphorus binders

  • chitosan (0.95%) to bind with uraemic toxins

  • astragalus (9.5%) for renal fibrosis

  • fish protein hydrolysate (1.9%) for hypertension

Binders containing magnesium are not really ideal for CKD cats because they can cause high magnesium levels in the blood, which in turn can sometimes cause urinary tract problems such as stones in some cats. Pet Education states "Do not use magnesium containing products in animals with kidney failure."

 

Chitosan is also contained in Ipakitine, see above.

 

Astragalus is thought to be an antioxidant but Holisticat states that astragalus should only be used short term in cats, see Holistic Treatments.

 

Fish protein hydrolysate is also found in Astro's Protein Powder, though I am not sure whether Pronefra contains enough to make a difference.

 

The recommended dose of Pronefra is 1 ml per 4 kg (9lbs) of cat twice a day, mixed with food or syringed directly into the cat's mouth immediately before or after eating. I do not yet know how much calcium carbonate this would contain.

 

Effect of a product containing the dietary phosphate binders calcium and magnesium carbonate associated with other reno-protectant substances (Pronefra) on blood parameters and mineral balance in adult cats (2014) Bernachon N, Fournel S, Gatto H, Monginoux P & McGahie D International Journal of Applied Research in Veterinary Medicine 12(1) pp8017 found that giving Pronefra to ten healthy 2-5 year old cats for twelve weeks led to decreased creatinine and phosphorus levels. Calcium and magnesium levels remained within normal range.

 

Comparative palatability of five supplements designed for cats suffering from chronic renal disease (2014) Bernachon N, Fournel S, Gatto H, Monginoux P & McGahie D Irish Veterinary Journal 67(1) p10 compared the palatability of five products intended for CKD cats: Ipakitine, Azodyl, Renalzin, Rubenal and Pronefra. The study, undertaken by employees of Virbac, the manufacturer of Pronefra, found that Pronefra was the most palatable.

 

I haven't heard from too many people who have used it as yet (May 2016), but one person said it made her cat vomit and a couple of people said their cats didn't like the taste. Personally, I don't think I would bother with Pronefra.

 

Calcium-based Binders Side Effects


Hypercalcaemia in cats (2001), a paper by Dr Chew presented to the World Small Animal Veterinary Association World Congress 2001 mentions that using calcium-based binders may cause hypercalcaemia. Thus, if you are using a calcium-based binder, frequent monitoring of blood calcium levels is essential. You should not use a calcium-based binder if your cat is taking calcitriol.

 

In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew 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 products such as famotidine (Pepcid AC) or omeprazole (Prilosec), I would discuss the situation with your vet.

 

In The role of phosphorus in feline chronic renal disease (2010) CVC in San Diego Proceedings,  Dr D Chew says that cats on calcitriol should not be given calcium-based phosphorus binders.

 

Effects of phosphorus binders in moderate CKD (2012) Block GA, Wheeler DC, Persky MS, Kestenbaum B, Ketteler M, Spiegel DM, Allison MA, Asplin J, Smits G, Hoofnagle AN, Kooienga L, Thadhani R, Mannstadt M, Wolf M & Chertow GM Journal of the American Society of Nephrology 23(8) pp1407-15 found that binders containing calcium acetate did reduce phosphorus levels but also caused calcium build up in blood vessels, which can lead to heart problems.

 


Sevelamer-based Binders: Renagel and Renvela


 

There are two types of sevelamer-based binders, sevelamer hydrochloride and sevelamer carbonate. Sevelamer-based binders are very expensive, but may be worth considering if you cannot use the other types of binders for some reason, though there is little evidence for their use in cats. In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference, Dr D Chew says "Many human clinical studies have demonstrated the ability of sevelamer hydrochloride to lower serum phosphorous, and parathyroid hormone levels, and control Ca x P product in dialysis patients compared with calcium containing phosphate binders.  Their effects on dogs and cats with clinical CRF, however, have not been reported."

 

Comparison of sevelamer hydrochloride and sevelamer carbonate: risk of metabolic acidosis and clinical implications (2009) Pai AB & Shepler BM Pharmacotherapy 29(5) pp554-61 found that sevelamer hydrochloride may increase the risk of metabolic acidosis, but that sevelamer carbonate did not appear to do so.

 

Renagel: Sevelamer Hydrochloride


Renagel (sevelamer hydrochloride) is a relatively new phosphorus binder approved for use in humans, with not much history of use in cats. Doctor's Guide has information on the approval of Renagel for use in the USA.

 

In Renal disease in cats (2013) Crieff 2 Day Small Animal CPD Meeting pp125-144 Prof D Gunn-Moore says "Some clinicians have also used sevelamer hydrochloride, but anecdotally this appears less effective than lanthanum."

 

Renvela: Sevelamer Carbonate


Renvela (sevelamer carbonate) is the next generation version of Renagel which contains a carbonate buffer. It is intended to help with bicarbonate levels.

 

Effects of phosphorus binders in moderate CKD (2012) Block GA, Wheeler DC, Persky MS, Kestenbaum B, Ketteler M, Spiegel DM, Allison MA, Asplin J, Smits G, Hoofnagle AN, Kooienga L, Thadhani R, Mannstadt M, Wolf M & Chertow GM Journal of the American Society of Nephrology 23(8) pp1407-15 found that binders containing sevelamer carbonate did reduce phosphorus levels but also caused calcium build up in blood vessels, which can lead to heart problems.

 

Sevelamer-based Binders Dosage Guidelines


 

ISFM Consensus Guidelines


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 state that the starting dose is 90-160mg/kg per day.

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 405-720mg of binder a day, spread over the cat's meals.

Dr Dennis Chew of Ohio State University College of Veterinary Medicine


In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew states "33-54 mg/kg PO q 8 hr; 50-80 mg/kg PO q12 hr."

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 150-240mg of binder three times a day or 225-360mg of binder twice a day, resulting in a daily total of 450-720mg of binder.

Sevelamer-based Binders Side Effects and Interactions


Sevelamer may cause constipation. Another more worrying problem is interference with blood clotting, so if you use it, it may also be necessary to give your cat Vitamin K. 

 


Iron-Based Binders: Lenziaren and Velphoro


 

Lenziaren


Lenziaren (also known as SBR759) is a new phosphorus binder for cats derived from iron oxide. It has been available in Japan and Taiwan since 2013 and presumably Novartis, the manufacturer, will be releasing it in other markets in due course.

 

Efficacy and acceptability of the new oral phosphate binder Lenziaren in healthy cats fed a renal diet (2015) King JN, Delport PC, Luus HG, Erasmus HL, Barnes PM & Speranza C Journal of Veterinary Pharmacology and Therapeutics 38(3) pp278–289 found that Lenziaren seemed to be well tolerated when added to food. Iron levels also increased, as you might expect from an iron-based binder, but so did food intake. This trial was conducted in healthy cats, and found that when these healthy cats were given higher doses of Lenziaren, their phosphorus levels actually increased. The manufacturer is currently investigating this.

 

Like me, you may be wondering why Lenziaren was fed to healthy cats. This is probably because, according to Scientific opinion on the safety and efficacy of Lenziaren (iron, aqua carbonate hydroxyl oxo starch sucrose complex) as a feed additive for cats (2013) Panel on Additives and Products or Substances used in Animal Feed European Food Safety Authority Journal 11(5) p3204-5, Lenziaren is "intended to be used in food for adult cats to reduce phosphate absorption in the gastrointestinal tract in order to prevent chronic kidney disease." Whilst phosphorus restriction may possibly be appropriate for older cats who may develop CKD in the near future (see Prevention), I would have thought feeding a somewhat lower phosphorus food would be a better first step. The panel concludes "Lenziaren has the potential to be efficacious in cats at the highest recommended dose of 1 g/cat per day (equivalent to 20 000 mg/kg feed). However, the FEEDAP Panel has some reservations regarding the value of its long-term use in healthy cats. The Panel concludes that there is a need for a post-market monitoring plan." In a revised version of the scientific opionion, found here, the panel "considers that Lenziaren has the potential to be efficacious in binding intestinal phosphorus at the minimum recommended dose of 0.25 g/cat per day."

 

Efficacy and acceptability of the new oral phosphate binder Lenziaren in healthy cats fed a renal diet (2015) King JN, Delport PC, Luus HG, Erasmus HL, Barnes PM & Speranza C Journal of Veterinary Pharmacology and Therapeutics 38(3) pp278–289 refers to earlier field trials which indicated that an effective dose for CKD cats was 0.5-2.0g per day, added to meals, and that, unlike the healthy cats in the above study whose phosphorus levels rose on higher doses, their phosphorus levels reduced at this dosage.

 

I have heard from a couple of people in those countries where Lenziaren is available who have used it in their CKD cats and found it effective. I think if I were to use it, I would monitor my cat's iron levels as well as phosphorus.

 

Velphoro


Velphoro (sucroferric oxyhydroxide), previously known as PA21, is a new binder which was launched in the USA in 2014 for humans on dialysis. It is also iron-based and comes in a chewable form. Apparently it binds phosphorus more effectively than sevelamer in human dialysis patients. The most common side effect is diarrhoea. I do not know anyone who has used it in cats as yet but will report further should that happen.

 

Iron-Based Binders Dosage Guidelines


 

ISFM Consensus Guidelines


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 state that the starting dose is 0.25-0.5g/kg per day.

 

A kg is 2.2 lbs, so for a 10lb (4.5kg) cat, you would give 1.125-2.25g of binder a day.

Lenziaren Guidelines


According to Scientific opinion on the safety and efficacy of Lenziaren (iron, aqua carbonate hydroxyl oxo starch sucrose complex) as a feed additive for cats (2013) Panel on Additives and Products or Substances used in Animal Feed European Food Safety Authority Journal 11(5) p3204-5, the minimum recommended dose of Lenziaren is 0.25g/cat per day and the highest recommended dose is 1 g/cat per day.

 


Which Binder to Choose


 

It can be difficult deciding which binder to use. Traditionally people used aluminium hydroxide, but this is now harder to find in the USA, and some people are uncomfortable about the possibility of aluminium toxicity. Many members of Tanya's CKD Support Group switched to lanthanum carbonate for these reasons, but following the discontinuation of Renalzin, it is not easy to find this cheaply.

 

Here is a summary of the pros and cons of each binder type, followed by my own experiences and thoughts. Ultimately, if your cat needs a phosphorus binder, I would say the most important thing is that s/he receives one.

 

Aluminium Hydroxide Pros and Cons


 

Pros


They are very effective, are available over the counter (at least in theory), are cheap, and have no taste or smell so most cats are prepared to eat them in their food.

 

Cons


They may cause constipation, may need to be tracked down in the USA, and there is a risk, albeit a relatively small one, of aluminium toxicity.

 

Lanthanum Carbonate Pros and Cons


Pros


They are very effective (as effective as aluminium hydroxide), have little taste or smell so most cats are prepared to eat them in their food, and (if you can obtain Renalzin) are relatively cheap.

 

Cons


Renalzin has been discontinued and alternative products are very expensive. Lanthanum-based products may cause constipation, and serious problems may be seen if given to patients who are constipated, diabetic or using a calcium channel blocker (such as amlodipine for high blood pressure).

 

Calcium-based Binders Pros and Cons


Pros


They are cheap, available over the counter and there are a variety of commercial preparations which are formulated to be palatable and to provide possible additional benefits (though these are not as cheap).

 

Cons


They do not bind phosphorus as effectively as aluminium hydroxide or lanthanum, and may cause elevated calcium levels. Some may also interact with stomach acid blockers such as famotidine (Pepcid AC).

 

Sevelamer-based Binders Pros and Cons


Pros


They may be helpful for cats who cannot use the other types of binder for some reason.

 

Cons


There is little history of use in cats but these binders appear to be less effective than lanthanum. They may cause problems with blood clotting, and may cause elevated calcium levels. Like many other binders, they can cause constipation.

 

Iron-based Binders Pros and Cons


Pros


Appear to be effective, based on limited studies and feedback I have received. One study found this type of binder seemed to improve appetite, though that study used healthy cats.

 

Cons


Not yet available in western countries. May be necessary to monitor iron levels as well as phosphorus levels. Phosphorus levels actually increased in the healthy cats who received this type of binder.

 

My Experiences


I have used aluminium hydroxide and Ipakitine (which is calcium carbonate-based) for my cats. I have not used lanthanum, sevelamer or iron-based binders.

 

Both aluminium hydroxide and Ipakitine worked just fine for my cats. As far as the Ipakitine went, Ollie did not have particularly high phosphorus levels to start with, whereas Thomas, who received aluminium hydroxide, did. My own vet in the UK has seen falls in creatinine and BUN (urea) in some cats when using Ipakitine and no other treatments.

 

In principle I would certainly be happy to try lanthanum carbonate, but since it is now horrendously expensive following the withdrawal of Renalzin from the market, I doubt I would bother.

 

Personally, I would probably reach first for aluminium hydroxide, not least because it is effective, easy to obtain in the UK and not too expensive.

 

However, if I had a cat in early stage CKD with moderately elevated blood phosphorus levels (between 6 and 7 mg/dl (USA) or 1.9 and 2.25 mmol/L (international) but normal blood calcium levels, I would consider using a commercial calcium carbonate preparation such as Ipakitine because my vet is very familiar with it, it is easy to source, not too expensive, and it may have additional benefits. I would ask my vet to monitor my cat's blood calcium levels.

 

For a cat with higher phosphorus levels (over 7 mg/dl (USA) or 2.25 mmol/L (international), or a cat with moderately elevated phosphorus levels but elevated calcium levels, I would definitely opt to use an aluminium hydroxide binder. Even for cats with lower phosphorus levels, if the cat's phosphorus multiplied by total calcium is higher than 70 in US values or 5 in international values, the cat is at risk of tissue calcification (see secondary hyperparathyroidism). In such a case, again I would opt to use an aluminium hydroxide binder in order to get the phosphorus levels under control as quickly as possible.  

 

Don't forget, if the binder you choose doesn't seem to be helping, or doesn't seem to suit your cat, you can always try another, either instead of or in addition to the binder you are using.

 

The most important thing, if your cat needs a binder, is to use one.

Combining Binders


If you are having trouble getting phosphorus under control using one type of binder alone, you can use another in addition to the first. This often is the case when people do not wish to give higher doses of aluminium hydroxide-based binders, so choose to add lanthanum carbonate.

 

In such cases, you would give the lower doses of aluminium hydroxide outlined above and then add lanthanum carbonate. A suitable starting dose of lanthanum carbonate might be 50-100mg per kg of cat per day, which equates to a bit less than 25-50 mg per lb of cat per day. You can go up to 200mg per kg of cat per day (just under 100mg per lb of cat per day) if necessary, but obviously work with your vet on determining the most appropriate dosage for your cat.

 

It is fine in this situation to mix the binders when you give them. So if, for example, you feed your cat three times a day, you can calculate how much aluminium hydroxide you need to give in total for the day and how much lanthanum carbonate you need to give in total for the day, and then give a third of each to your cat with each meal.


How to Give Binders


See above for recommended dosages.

How to Mix Binders with Food


Phosphorus binders must be given with food so they can bind with the phosphorus in it. Aluminium hydroxide binders are usually odourless and tasteless if you choose carefully, but since they are a natural (mined) product, they can sometimes add a bit of a gritty texture to food or make it taste a little drier. Lanthanum carbonate binders are also supposed to be odourless and tasteless but some people think Renalzin tastes bitter. Calcium-based binders can taste a bit chalky.

 

People used to be confused that the dosage of phosphorus binder recommended did not take into account the size of the meal being consumed. Specialists such as Dr Chew in Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference are now advising that "The dose of any phosphate binder should be based on the meal size (phosphorus intake) and the prevailing serum phosphorus level for each CKD patient; the dose is titrated to effect." Obviously this is the ideal, so if you know, for example, that your cat always eats larger meals in the evening than in the morning, you can adjust the dose accordingly.

Giving Binders with Canned Food


  • tablets can simply be crushed and added to the food.

  • capsules can be opened and the contents mixed with the food (after measuring as above).

  • liquid binders can either be mixed in the food or syringed into your cat's mouth just before eating.

  • one retailer recommends adding a teaspoon of water to the tinned food and binder and letting it stand for ten minutes before serving in order to let the binder mix thoroughly. This may help remove any grittiness.

 

Giving Binders with Dry Food


  • try putting the food in a freezer bag together with the crushed or powder binder and leave them to mingle overnight.

  • if you are using a liquid binder, you can syringe it into your cat's mouth just before eating.

How Long For Binders to Work


You should see an improvement in your cat's blood phosphorus levels after 7-10 days. You may see a difference in your cat's demeanour sooner than this. Check your cat's phosphorus level every two weeks until the level is acceptable, then check it every 2-3 months to see if any adjustments to your treatment plan are necessary.

 

Please see The Importance of Phosphorus Control for information on your phosphorus goal and how to monitor your cat's phosphorus levels.

 

Monitoring Phosphorus Levels


In theory, a cat receiving binders may develop the opposite of what you are trying to treat, i.e. low phosphorus levels (hypophosphataemia). In Chronic kidney disease (CKD) in dogs and cats - staging and management strategies (2015) A Presentation to the Virginia Veterinary Medical Association 2015 Virginia Veterinary Conference,  Dr D Chew states "it is difficult for this to develop in those with initially high concentrations of serum phosphorus." However, in Renal disease in cats (2013) Crieff 2 Day Small Animal CPD Meeting pp125-144 Prof D Gunn-Moore says "Since hypophosphataemia can result in weakness and anaemia, it is important to monitor phosphate levels whichever type of phosphate binder is chosen."

 

Please see The Importance of Phosphorus Control for information on your phosphorus goal and how to monitor your cat's phosphorus levels.

How to Manage with Multicat Households


Try not to let your non-CKD cats eat food containing phosphorus binders. This is particularly important for kittens, who need twice as much phosphorus each day as a healthy cat because they are still growing.

 

However, if your healthy adult cats eat a small amount of food containing binders occasionally (say once or twice a week), this should not be a problem as long as you make sure that most of the food they eat does not contain binders.

 

If you have to go to work each day and do not want to separate your cats, one possible solution might be to leave out prescription kidney dry food for all your cats to eat, but to give your healthy cats normal food the rest of the time. Be guided by your vet.

 

If you are in the USA, you could also consider using Conseal AlH as discussed below.

 


Where to Buy Phosphorus Binders


Please read above about which binder to use and why.

 

If you buy aluminium hydroxide, you may see an expiration date on it. This is usually to comply with pharmacy laws, but in practice, since aluminium hydroxide is a mineral that is mined from the earth, it cannot really expire, so I would not worry too much about expiry dates.

 

Be careful about your source for aluminium hydroxide. Some people try to buy products that are not pharmaceutical grade, often from ebay. These are not pure enough and are not suitable for CKD cats.

 

Sources - USA


 

Aluminium Hydroxide USA


 

Loose Aluminium Hydroxide


Loose aluminium hydroxide in gel or powder form is a popular choice because it is odourless and tasteless, so is much easier to give. There are three main generic brands available, Spectrum, Gallipot and PCCA.

 

Loose aluminium hydroxide used to be available tubs from a number of online pharmacies, but the only one which definitely still sells it these days is Thriving Pets, though most local compounding pharmacies should be able to order it for you. It may take a local pharmacy a few days to obtain it for you; it is fine to wait that long. You may be told that a prescription is required, but this is not correct, the gel and powder formulations are over the counter products.

 

If you need aluminium hydroxide quickly, it is probably

 

Thriving Pets

Sells 500g (1.1 lbs) of aluminium hydroxide dry gel for US$79.95 plus shipping. They also sell 1 oz at a time, as well as capsule or liquid (oral) formulations (these require a prescription, which the gel formulation does not) . 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.

 

Phos-Bind


Phos-Bind is a newer brand of loose aluminium hydroxide binder made by Rx Vitamins. It is essentially a tub of loose aluminium hydroxide powder in a 200g size (just over 7 ounces).

 

VetRxDirect

Sells 200g (a bit less than 8 oz) for US$29.29 with free shipping on orders over US$49, shipping costs US$4.99 for orders below this.

 

PureFormulas

Sell Phos-Bind for US$36 with free shipping.

 

Amazon

Has a marketplace seller selling 35g (about 1.25 oz) of Phos-Bind for US$20 including free shipping.

 

Amazon

Has another seller selling 200g (a bit less than 8 oz) for US$39.99 with free shipping if you spend US$49 or more.

 

ConSeal AlH


Conseal AlH are aluminium hydroxide 200 mg chews made by Bock Pharma. They come in a box of 28 individually wrapped chews. The recommended dose is 1-2 chews per 10 lbs of cat given with meals. If you need to give less, the chews are semi-soft so can be broken or cut into pieces. In this form they can be mixed with food, but one member of Tanya's CKD Support Group found the chews very helpful for her cat who missed getting treats, and gave them before her cat's meals. They could also be useful for multi-cat households where you can give your CKD cat a Conseal treat whilst giving your other cats ordinary treats.

 

Conseal AlH apparently has to be ordered through your vet, and a pack costs about $20-$25.

 

Drugs has some information about Conseal AlH.

 

AlternaGel or Amphojel


If you buy your binders from your vet, you will often be offered an aluminium hydroxide-based binder called AlternaGel, but this is peppermint flavoured, which most cats hateAlternaGel also contains potassium citrate.

 

Amphojel, another product which vets sometimes stock, comes in both unflavoured and peppermint flavoured version, so check before you buy that you will be getting the unflavoured one; most vets only seem to stock the peppermint-flavoured version.

 

Fosrenol and Renalzin USA


Costco

sells thirty 1000mg Fosrenol tablets for US$364.77 or 50 for US$589.01. You have to buy them from your local Costco pharmacy with a prescription but you do not have to be a member of Costco to use their pharmacies.

 

Thriving Pets

Sell ninety Fosrenol 500mg or 1000mg tablets for US$999.95. 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$100. Shipping is free for orders over US$100 after the discount.

 

VioVet

In the UK, sells Renalzin for £8.40 for 50ml or £22.34 for 150ml. For parcels weighing less than 2kg (4.4lbs), shipping is a flat rate £10 and delivery usually takes 2-3 weeks. This pharmacy has shipped Renalzin to US members of my support group with no problems. Renalzin is being discontinued by the manufacturer, so supplies will run out some time during 2015.

 

Epakitin USA


Entirely Pets

Sells Epakitin for US$16.49 (50g), US$43.99 (150g) or US$68.99 (300g).

 

Medi-Vet

Sells Epakitin for US$22.82 (50g), US$54.99 (150g) or US$76.16 (300g).

 

Sources - UK


 

Aluminium Hydroxide UK


Alucaps are an odourless and flavourless phosphorus binder made by 3M, and are your best bet in the UK. They are available as follows:

 

Members of Tanya's CKD Support Group in the UK have successfully obtained Alucaps from Boots, Lloyds and Superdrug during 2015, though some people have found it harder in 2016. In August 2014 Alucaps cost around £12 for 120 capsules of 475mg aluminium hydroxide from many branches of Boots and other chemists, but since then many people have been asked to pay as much as £16-20. Don't say they are for a cat, or they may ask for a prescription from your vet, whereas if you buy them for your own indigestion, they are over the counter. When I asked for Alucaps in Boots, the pharmacist had never heard of them, but - unbeknownst to her - she did actually have some in stock; so you may need to be persistent or ask for them to be ordered for you. If they need to be ordered, they should only take a couple of days to arrive, and it is fine to wait that long

 

Clear Chemist

Sells Alu-caps online at £16 for 120. As far as I can see, they do not require a prescription(though do not say they are for a cat), and I am told they deliver quickly. Clear Chemist will ship to some other countries, particularly in Europe.

 

Lloyds Pharmacy

Sells Alucaps online for 17p per capsule (so 120 capsules cost £20.40) plus £3.95 delivery, though for some reason they require a prescription if bought this way.

 

Renalzin UK


VioVet

In the UK sells Renalzin for £8.40 for 50ml or £22.34 for 150ml. Delivery costs £2.99 for orders under £29, and is free otherwise. Renalzin is being discontinued by the manufacturer, so supplies will run out some time during 2015.

 

Ipakitine UK


VioVet

Sells Ipakitine for £9.48 for 60g.

 

Vetscriptions

Sells Ipakitine for £11.90 for 50g.

 

Best Pet Pharmacy

Sells Ipakitine for £12.80 for 60g.

 

All these sellers also sell the larger 180g size.

 

Sources - Canada


 

Aluminium Hydroxide Canada


Pet Pharm

Sells an aluminium hydroxide based binder called Basaljel made by Axcan Pharma Inc. It comes in gelcaps, each containing 500 mg of aluminium hydroxide, and they cost CAN$26.95 for 100. Basaljel is also available over the counter in many Canadian pharmacies.

 

Xenex Laboratories

Sells 500g of aluminium hydroxide, you can contact them to check the current price, but for reference, in March 2016 one member of Tanya's CKD Support Group paid CAN$90 including shipping to Newfoundland.

 

Canada Drugs

Sell a liquid aluminium hydroxide product called Alugel for CAN$17.65, but unfortunately this is mint-flavoured, which does not appeal to many cats.

 

Renalzin Canada


VioVet

In the UK sells Renalzin for £8.40 for 50ml or £22.34 for 150ml. For parcels weighing less than 2kg (4.4lbs), shipping is a flat rate £10 and delivery usually takes 2-3 weeks. This pharmacy has shipped Renalzin to US members of my support group with no problems. Renalzin is being discontinued by the manufacturer, so supplies will run out some time during 2015.

 

Sources - Australia and New Zealand


Alu-Tabs, made by iNova Pharmaceuticals, are probably your best bet. They come in 600mg tablets rather than a powder, but I imagine you could crush them. They should be available over the counter in pharmacies, though your pharmacist may not realise they are there. Don't say they are for a cat, or they may ask for a prescription from your vet, whereas if you buy them for your own indigestion, they are over the counter.

 

Home Pharmacy

Sells 100 Alu-Tabs for AUS$32.69 (I do not know anybody who has used this pharmacy as yet).

 

 

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This page last updated: 06 June 2016

Links on this page last checked: 06 May 2015

   

 

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TREATING YOUR CAT WITHOUT VETERINARY ADVICE CAN BE EXTREMELY DANGEROUS.

 

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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Copyright © Tanya's Feline CKD Website 2000-2016. All rights reserved.

 

This site was created using Microsoft software, and therefore it is best viewed in Internet Explorer. I know it doesn't always display too well in other browsers, but I'm not an IT expert so I'm afraid I don't know how to change that. I would love it to display perfectly everywhere, but my focus is on making the information available. When I get time, I'll try to improve how it displays in other browsers.

 

You may print out one copy of each section of this site for your own information and/or one copy to give to your vet, but this site may not otherwise be reproduced or reprinted, on the internet or elsewhere, without the permission of the site owner, who can be contacted via the Contact Me page.

 

This site is a labour of love, from which I do not make a penny. Please do not steal from me by taking credit for my work.

If you wish to link to this site, please feel free to do so. Please make it clear that this is a link and not your own work. I would appreciate being informed of your link.