TANYA'S

  FELINE CHRONIC RENAL FAILURE

INFORMATION CENTRE

TREATMENTS

Introduction

In the UK, the treatments most commonly offered by vets are low protein prescription food, anabolic steroids, B vitamins and just lately benazepril, an ACE inhibitor with the trade names of Fortekor in the UK and Lotensin in the USA, which has recently been licensed in the UK, Australia and parts of Europe for the treatment of renal insufficiency in cats. While all these treatments have some merit and are included here, there are many others which can also help, as can be seen below. Please click on the links above for the information you need. Immediately below are additional sub-headings for some of the above topics.

2. phosphorus binders, and why they are so important

   • binder types

   • aluminium binders

     • dosage

   • calcium binders

   • other types of binders

Most CRF cats will eventually need some kind of fluid therapy in order to maintain hydration levels. When cats "crash" and are in crisis they are usually severely dehydrated and intravenous fluids (IV) at the vet's may be required for several days - Thomas had these twice and they were very effective. Of course, ideally you do not want things ever to progress to this stage, so to avoid dehydration in the first place, fluids may be given under the skin at home (sub-cutaneous fluids). Fluid Therapy is so essential in the treatment of CRF that it has its own page. Cats with proteinuria may benefit from using ACE inhibitors.

Constipation

Treating or preventing constipation can make a big difference to your cat's quality of life. It is important to keep a close eye on your cat's litter tray and to deal promptly with any signs of constipation or straining (see Symptoms).

Some cases of constipation are caused by low potassium levels or by high calcium levels. Treating these problems may resolve or improve the constipation.

Fluid therapy can help reduce constipation, but it is quite likely that you will have to use other methods at some point. If at all possible, you want to avoid the need for an enema or manual evacuation of the bowel by your vet. Many vets seem to routinely prescribe Laxatone or Petromalt, but these are really intended for the treatment of hairballs and are not ideal - or particularly effective - for the ongoing constipation problems suffered by many CRF cats, plus they may prevent the absorbtion of nutrients if used longer-term. However, such a product may be of use if given for a short period to try and soften the hard stool often seen at initial diagnosis.

Slippery Elm Bark can be sufficient to keep some CRF cats regular; there is more information on this treatment in Holistic Treatments. 

Lactulose

Lactulose is probably the most popular treatment specifically to prevent constipation on the Feline CRF Information list. It is a syrup of long chain indigestible sugars (derived from lactose, a milk sugar) that pulls water into the colon and softens the stool. Lactulose is available OTC in Europe and Canada, but requires a prescription in the USA. Lactulose is a "dose to effect" treatment, so you should start with a low dose, and work your way up only if necessary (so as not to cause the opposite problem of diarrhoea). A possible starting dose is 0.5ml once a day, but this may need to be adjusted with your vet's approval; Plumb's Veterinary Drug Handbook says that cats may be given up to 1ml per kg (0.5ml per lb) of bodyweight per day. It does take a couple of days for lactulose to work, so do not give too much too soon. I found out the hard way that, if you syringe it in to your cat's mouth, it's a good idea to wipe your cat's chin with a damp cloth after using it, because, being sugar-based, it is incredibly sticky. You may find it easier to mix the lactulose with food; some people use a little babyfood each day for this purpose.

A 1997 review of renal failure in humans (Lactulose and renal failure Vogt B & Frey FJ, Scandinavian Journal of  Gastroenterology Supplement 222 pp100-1) indicated that lactulose may help promote the excretion of BUN and creatinine through the faeces, and some people have found that this effect is sometimes seen in CRF cats; but lactulose is not usually given specifically or solely for this purpose because of the obvious side effects of causing diarrhoea in non-constipated patients. The British Medical Journal reports on a recent study of human patients that indicates that lactulose may also help to prevent urinary tract infections.

Since lactulose is a prescription item in the USA, it can be rather expensive, but Walmart and Target both sell it for US$4 a bottle.

Since lactulose is so sticky, you might wish to ask your vet about a new form of it called Kristalose. This is a powder which can be dissolved in water, and which therefore eliminates the stickiness problem. I do not know anybody who has used it for a cat yet, but it is available from Drugstore in the USA.

Mar Vista Vet discusses lactulose.

Drs Foster and Smith have some information about lactulose.

West Shore Endoscopy Center also has information about lactulose.

Lactulose Cautions

Some people have found that their cats developed hypercalcaemia (high calcium levels) after using lactulose regularly, which then improved when they stopped using lactulose. You may therefore wish to avoid lactulose if your cat is already hypercalcaemic. A possible alternative would be Miralax.

Lactulose is usually of limited use if a cat is so constipated as to have impacted stool; this may need to be removed by the vet before starting lactulose.

Antibiotics may reduce the effectiveness of lactulose. 

Lactulose may not be suitable for cats who also have IBD.

Lactulose may exacerbate the effects of diuretics. Drugs.com has more information about this.

Miralax

Miralax is a human constipation treatment containing polyethylene glycol 3350 (also known as PEG) which was recently made OTC in the USA, and perhaps as a result more people are gradually starting to use it on their cats, although I am not aware of any veterinary links about Miralax as yet.

Miralax is an osmotic laxative like lactulose, but unlike lactulose, which is a sticky syrup, it comes as an odourless and tasteless powder which can be mixed with water. Another advantage is that it does not have the potential to cause hypercalcaemia (high calcium levels) like lactulose does. In addition, since Miralax is now OTC, you do not need a prescription for it, though please do not use it without your vet's knowledge and approval.

A common starting dose is 1/8 of a teaspoon, though you can increase to 1/4 of a teaspoon if necessary. You can divide this between your cat's meals, there is no need to give it all in one go.

I have been asked why there is a warning on Miralax stating that it should not be used in patients with renal failure, particularly since this warning is not on generic products. Miralax is often used to empty the bowel before an endoscopy. If you use it for this purpose, it may cause an imbalance in the body's electrolytes, particularly potassium and sodium. Since CRF patients have a tendency towards electrolyte imbalances anyway, this could be risky for a CRF patient. However, when giving Miralax to a CRF cat in order to prevent constipation becoming a problem, you are using Miralax in a different way which should not affect electrolytes in any way. But of course do check with your vet anyway before using Miralax.

In the UK, Miralax is not available but other products containing its active ingredient (polyethylene glycol 3350, or PEG) are available. Two such brands are Idrolax and Movicol. Unfortunately Idrolax contains orange oil, which is potentially problematic, and which is unlikely to appeal to your cat (most cats find citrus repellent). Movicol unfortunately contains added electrolytes. This is presumably to offset the electrolyte imbalances which may result from using these products pre-endoscopy, but since CRF cats are not receiving Movicol for this purpose, the added electrolytes mean this product is unlikely to be appropriate.

There is also another type of polyethylene glycol available, which is polyethylene glycol 4000, known as Macrogol 4000 and also sold under the Idrolax brand name. As far as I can tell, this does not appear to contain electrolytes, but since it is also Idrolax, it may also contain orange oil. In addition, I do not know if this higher strength is suitable for cats. It might be acceptable given at a reduced dose, but this is something you would need to discuss with your vet before using it. Net Doctor has some information about Macrogol 4000.

Other products containing polyethylene glycol 3350 are available in Canada but many of these also contain additional inappropriate ingredients. However, Miralax itself is available from Canada Pharmacy.

Fibre

Sometimes it is also necessary to add fibre to your cat's diet in order to bulk up the stool so that it moves easily through the cat's system. Some  form of vegetables such as baby or tinned peas or pumpkin (not the pie filling) may suffice - tinned pumpkin is harder to find in the UK, but apparently some branches of Waitrose sell American canned pumpkin with no additives in the canned vegetables aisle. You should start gradually, say with half a teaspoon of pumpkin once or twice a day (it can be mixed with food), and increase as needed. You can freeze unused pumpkin in ice cube trays and just take out what you need for each day.

Alternatively if you are in the UK, your vet may offer you a standardised pharmaceutical-grade fibre called Nutrifyba. A popular fibre-based treatment which is available OTC in the USA is psyllium, commonly sold under the name of Metamucil. You only need to give a tiny amount - the maximum dose is 1/8th of a teaspoon, but you should start with an even smaller dose. With fibre-based treatments, it is very important to ensure that the cat drinks plenty of water, otherwise the fibre can bulk up in the body and make the constipation worse. Please note these fibre-based treatments are intended to help prevent constipation, but they cannot cure it  once it is present.

Other Constipation Treatments

Some people whose cats have megacolon (a bowel disorder which causes severe constipation) have found that giving vitamin B12 in the form of methylcobalamin is helpful. See Food Composition & Nutritional Requirements for more information on vitamin B. It also appears that ranitidine (Zantac) may help some cats with constipation, according to the study below.

Feline constipation, obstipation, and megacolon: prevention, diagnosis, and treatment Washabau RWorld Small Animal Veterinary Association World Congress 2001 has information on constipation. It mentions that ranitidine (Zantac) may help with constipation caused by low motility in the colon.

The Feline Advisory Bureau has a helpful overview of constipation.

Constipation Cautions

You may be offered Prepulsid or Propulsid, which is a drug called cisapride, but I would suggest only using this as a last resort since it has been withdrawn from the human market because of serious heart-related side effects which have caused some human deaths (Rx List has more information about this issue in humans, while Pet Education has some information about the implications for animals).

As mentioned above, hairball remedies are also best avoided for ongoing use to treat constipation, because, as mentioned by the Merck Veterinary Manual, they may interfere with the absorption of nutrients if used longer-term.

Mineral oil (liquid paraffin) should not be used, because it can easily be aspirated and cause pneumonia. If given regularly, it may also interfere with the absorption of nutrients. Merck Veterinary Manual explains more about this.

Enemas containing sodium phosphate (one common US brand is Fleet) should also be avoided because they are extremely dangerous for cats.

Electrolyte abnormalities induced by hypertonic phosphate enemas in two cats (1985) Jorgensen LS, Center SA, Randolph JF, Brum D, Journal of the American Veterinary Medical Association 187 pp1367-8 reports on two cats who suffered severe problems after such enemas, and advises against their use for cats with renal problems in particular.

The Merck Veterinary Manual also advises against the use of such enemas.

Urinary Tract Infections

These are often treated with antibiotics, and it is quite possible that your CRF cat will need antibiotics at some point, either for this reason or for mouth ulcers. One human study, Establishment of a persistent Escherichia coli reservoir during the acute phase of a bladder infection (2001) Mulvey MA, Schilling JD & Hultgren SJ Infection and Immunity 69(7) pp 4572-9 found that in some cases the bacteria that cause urinary tract infections can burrow so deep into the bladder lining that they cannot be detected in the usual tests. In a later (2004) study reported by Science Daily, researchers found that the bacteria commonly involved in UTIs pass through four distinct developmental stages, including a dormant stage in some cases which may help explain why UTIs often recur. In order to be sure that the bacteria are completely eradicated and the infection completely cured, CRF cats are often given a prolonged course of antibiotics, for four or five weeks or longer. This is even more important for a cat with a kidney infection, where a 4-6 week course of antibiotics should be given.

Some vets tend to put CRF cats on a low level dose of antibiotics on an ongoing basis, or recommend pulse dosing, where the cat is given antibiotics at regular intervals for several days at a time, e.g. for the first five days of every month. If your vet wishes to do this, discuss it and decide whether you think it is a reasonable treatment for your cat: infections can be hard for the weakened immune system of a CRF cat to cope with and to recover from, so in some cases this is not an unreasonable option. There is information on commonly used antibiotics below.

In light of the study at the Washington University in St Louis School of Medicine mentioned above, a new treatment for urinary tract infections has been developed called D-Mannose, which may also be helpful as a preventative. This product is supposed to be very helpful when dealing with infections where the bacteria have burrowed into the bladder wall. D-Mannose is a type of sugar, and it works by attracting the bacteria to bind with itself rather than with the bladder wall; the bacteria can then be passed out with urination. However, D-Mannose will only work for urinary tract infections caused by E coli (which accounts for 90% of all urinary tract infections in humans, and which is commonly the cause of feline urinary tract infections too). I do not know of anybody who had tried this treatment on their cat.

Dr Pressman has more information on the use of D-Mannose in humans.

Alternative Bladder Infection Solution is another human site which explains more about how D-Mannose works.

Sometimes cranberries are recommended for humans with urinary tract problems, but you should avoid giving cranberry or food containing cranberry to CRF cats - cranberries are too acidic for CRF cats, who tend towards acidosis anyway. In any event, the active ingredient in cranberries is Mannose, so you could consider giving D-Mannose instead.

The British Medical Journal has information about a recent human study which showed that lactulose (which is normally used for constipation) may help prevent urinary tract infections in humans.

Washington State University College of Veterinary Medicine has information on urinary tract infections and obtaining a urine sample.

Urinary tract infection: how to diagnose and treat correctly (2003) is a presentation by Claudio Brovida to the World Small Animal Veterinary Association World Congress 2003, which explains why lengthy courses of treatment are sometimes necessary.

Kidney Infections (Pyelonephritis)

Pyelonephritis is a bacterial infection of the kidneys. The cat may also have a lower urinary tract infection -  in some cases, untreated lower urinary tract infections rise into the kidneys - but not always. Cats with PKD are particularly prone to pyelonephritis, since the bacteria can burrow into the cysts. Our PKD cat, Harpsie, gets regular bouts of pyelonephritis.

Feline Advisory Bureau covers spraying and soiling indoors.

Weight Loss

Diet can of course often help with weight loss, and is such an important issue for CRF cats that there are separate pages on Food Composition and Nutritional Requirements, Which Foods to Feed and Persuading Your Cat To Eat. 

Weight loss can also be improved by treating the symptoms which are causing poor appetite, such as stomach acid, and/or by treating electrolyte imbalances; some vets also prescribe anabolic steroids as a matter of policy to act as an appetite stimulant and to help build muscle. In cats whose weight loss is associated with proteinuria (see What Do All Those Test Results Mean?), the use of the ACE inhibitor benazepril (Fortekor/Lotensin) may help. Treating metabolic acidosis can often help minimise weight loss. British vets often do not bother to monitor weight, but it can be a useful guide so try to weigh your cat regularly. Many people use baby scales to monitor their cat's weight at home. 

Proteinuria

Proteinuria is the leaking of excessive amounts of protein into the urine. It may cause foamy urine, weight loss and swollen legs, face and abdomen. Its presence may make the CRF progress faster.

There is some evidence that ACE inhibitors, such as benazepril (Fortekor or Lotensin) or enalapril (Enacard) may help with this problem. Feeding a low protein but high quality protein food may be of some use, as may omega 3 essential fatty acid supplements. However, there is as yet no definitive evidence that these treatments are of benefit to cats with proteinuria.

Assessment and management of proteinuria in dogs and cats: 2004 ACVIM Forum Consensus Statement (Small Animal) (2004) Lees GE, Brown SA, Elliott J, Grauer GF & Vaden SL Journal of Veterinary Internal Medicine 19 pp377-385 gives suggestions for the diagnosis and treatment of proteinuria.

Fluid Retention/Build-Up

Sometimes a CRF cat may develop problems with fluid retention, particularly if s/he is receiving too much fluid, either via IV or sub-QS, and/or has a heart problem. Fluid may collect in the lungs (pulmonary oedema), or around the lungs (pleural effusion) or in the abdomen (ascites). Cancer Back Up explains more about pleural effusion. Health A to Z explains more about ascites. 

If your cat feels "squishy" when you stroke him or her, this may indicate fluid retention, in many cases caused by overhydration from excessive sub-Qs. The cat may also show loss of appetite, because the fluid may be pressing on the stomach causing a feeling of fullness. Over-hydration may also cause hypertension. In such cases, you may find that reducing the amount or frequency of sub-Qs solves the problem; so speak to your vet about this. The Intravenous Fluids and sub-Cutaneous Fluids page has information on amounts and frequency of fluids. 

Sometimes fluid retention may become more serious, and in the worst cases may lead to or be caused by congestive heart failure. If your cat has loss of appetite, appears to be gaining weight rapidly or suddenly, particularly if he/she also starts coughing and/or develops a nasal discharge, you need to see a vet quickly. If s/he starts breathing with the mouth open or has a limp, this is a medical emergency indicating heart problems and you need to get to a vet as quickly as possible. Your vet will probably arrange an x-ray which will show clearly whether there is fluid in or around the lungs or abdomen. If there is a lot of fluid, they will arrange to remove it either manually via thoracentesis (if the fluid is pleural effusion, around the lungs) or by using a type of drug called diuretics.

Do not give sub-Qs to a cat exhibiting any of the above symptoms until you have spoken to your vet. You should also never give a cat sub-Qs until the fluids from the previous session have been absorbed. 

If your cat does exhibit these problems and you can afford it, I would recommend a visit to a feline cardiologist to discuss future treatment options for your cat. It may still be possible to give sub-Qs in the future if your cat needs them, but it is a careful balancing act between the needs of the kidneys and the needs of the heart.

If your cat is prone to overhydration, I would recommend weighing him or her daily, so you can be alert to possible problems.

Warning signs for congestive heart failure is a helpful site by an individual whose cat, Coco, had both CRF and heart problems, and gives useful information on what to watch for. Coco lived with CHF for quite some time.

Weight Gain

Most people are delighted when their CRF cat gains weight, and certainly if weight gain is slow and steady, this is good news. However, if your cat gains weight very quickly - I have heard of people who are delighted because their cat has gained 2 lbs in a week, a phenomenal rate of weight gain as a percentage of the average cat's size -  you need to investigate the cause. A sudden increase in weight, particularly if your cat is receiving sub-Q fluid therapy, can indicate fluid retention and possibly heart problems. If your cat feels "squishy" when you stroke him or her, this may also indicate overhydration. If your cat appears to be gaining weight rapidly or suddenly, particularly if he/she also starts coughing and/or develops a nasal discharge, starts breathing with the mouth open or has a limp, you should contact your vet as soon as possible. Further information on fluid retention and heart problems can be found on the Related Diseases page. If your cat is prone to such problems, you may wish to monitor your cat's weight with baby scales.

Tanita Digital Baby Scales 1584, which weigh in one ounce (20g) increments, are very popular on the CRF Information List. The recommended retail price is USD195, and you can buy them from Precision Weighing Balances for this price. You might also be able to buy a set of scales secondhand from Ebay or similar.

Total Body Works sells the same scales for US$140, with a three year guarantee.

Babycenter sells Redmon baby scales for US$48.97. I have these and like them.

Drs Foster & Smith sell cat scales for US$79.99.

Dry Coat

Slippery Elm Bark is often used to control stomach acid and to help with mouth ulcers, but as a side effect it often improves the cat's coat.  

The Regulation of Waste Products in the Body

Fluid Therapy

Fluid therapy not only helps to maintain hydration but it may also help with minimising toxins in the cat's blood, though it should not be used solely for this purpose. See fluid retention above for important information.

Enhancing Aromas

Human CRF patients have reported that their sense of smell and sometimes taste are impaired; this is thought to be caused by uraemic toxins. Making the food more attractive e.g. by heating it, may help encourage a cat to eat. See Persuading Your Cat To Eat for more information.

Controlling Stomach Acid

Stomach acid is very common in CRF cats, and treating it if it is present can make the cat feel much more comfortable, and may help with loss of appetite. Commonly used treatments are:

• slippery elm bark

• acid blockers

   

  • famotidine (Pepcid AC)

  • ranitidine (Zantac 75)

  • cimetidine (Tagamet)

   

• metoclopramide (Reglan)

• ondansetron (Zofran)

• pepto-bismol

• raising food bowls

• feeding before bedtime