This page is currently undergoing updating - thank you for your patience while this is in progress.
Note: this section is intended for veterinary surgeons only and should NOT be used by cat guardians to attempt to treat cats themselves. However, before leaving the page, guardians please download the following to take to your veterinary surgeons:
FIP diagnosis algorithm (this will open in a new window)
Note - these downloads should open in a new window and in some browsers will simply automatically download.
Click here for printer friendly version (i.e. black writing on white background) (this version is still the old page: until that is updated, you'd be better with the FIP treatment summary which is a printable pdf giving drugs and doses )
When I first came to Feline Infectious Peritonitis research, FIP was regarded as an incurable condition. Most reported "recoveries" were probably curable conditions wrongly diagnosed as FIP. However, it is my belief that if diagnosed early enough, some cats with FIP can be cured. With the introduction of feline interferon and more recently, FCoV protease inhibitors, we now see a glimmer of hope: treatment can occasionally effect a remission, sometimes for months and some cases recover completely. However, a lot more work requires to be done: even in human beings there is no reliable treatment for chronic inflammation. Therefore the emphasis must still be on totally preventing cats ever developing FIP in the first place, and on accurate diagnosis, so that cats with non-FIP conditions are not needlessly euthanased.
This webpage represents only the personal opinions of the author, not all opinion leaders agree with me.
1. DOUBLE CHECK THE DIAGNOSIS
To see me working through FIP diagnosis algorithm on a real life case, watch "Does Pancho Have FIP?" (It will count for 15 minutes of Continuing Professional Development.) More cases will be uploaded to YouTube. Also see the FIP diagnosis webpages.
The beauty of altering nutrition immediately is that it will help in any condition, not just FIP – and it is safe. If you have read The China Study, watched Forks Over Knives, or heard Dr Michael Greger’s famous top human killer diseases lecture, you will already be familiar with the enormous impact diet has on preventing, and even curing, most of the main reasons for human deaths - the situation in cats and dogs may well be similar.
Unlike humans, arginine is an essential amino acid in the cat (Morris & Rogers, 1978): this is why they are obligate carnivores. Arginine is essential not only for the urea cycle but also for the normal functioning of monocytes and endothelial cells. To see an animation of feline coronavirus infecting a monocyte/macrophage, and wet FIP developing, visit: http://www.youtube.com/watch?v=6RyI2LI9R9Q
Cereal based foods contain too much omega 6 polyunsaturated fatty acids and too little omega 3, leading to a state of chronic inflammation – we have seen this in human beings over the past couple of decades: an unprecedented rise in inflammatory conditions such as allergies, asthma and arthritis. We see a similar rise in inflammatory conditions being recognised in the cat.
FCoV associated diarrhoea helped by chicken and pumpkin cat food
You can get a discount on these cat foods at Zooplus by following this link:
Nucleoside analog GS-441524
Another exciting revelation from Dr Pedersen's group is the results of an anti-viral drug called GS-441524. Preliminary investigations showed that it was without side effects and experimentally infected cats recovered and were alive 8 months post-treatment. (Murphy et al, 2018)
Dose: GS-441524 treatment at a dosage of 2 or 5 mg/kg SC sid for 2 weeks.
GC376 is a 3C-like protease inhibitor antiviral drug, not currently commercially available. In the most recent field trial, 7 of 20 cats experienced remission. Here is a figure from the publication by Prof Pedersen et al:
As you would expect, the anti-viral was most effective against cats with the acute form of FIP, effusive FIP, but less so against non-effusive FIP.
Updates on this experimental drug can be found at www.sockfip.org.
Interferons are the broad-spectrum antivirals that the body produces. They are fairly species specific, so it is more effective to use feline interferon than human interferon, although the latter is better than nothing.
interferon omega (Virbac, France)
IFN omega was initially given subcutaneously at 1 MU/kg every other day, and then twice every week for variable period if remission was seen.
(dexamethasone 1 mg/kg intrathoracic or intraperitoneal injection
once only) or prednisolone. Oral prednisolone was initially given
at 2 mg/kg once daily, and the dosage was gradually tapered to 0.5
mg/kg every other day after remission.
Remember that reconstituted, diluted Virbagen Omega
lasts only up to 3 weeks in the fridge.
Updates on treatment will appear in the English version of the website before the translated pages.
Suppliers: Virbagen Omega can be obtained from your Virbac representative. From abroad, it can be bought at Abbeyvet, who can be contacted at email@example.com.
In the USA, Virbagen Omega is stocked by The Animal Medical Centre, 510 East 62nd Street, New York, NY 10065. Telephone: (212)-329-8724
In effusive FIP 30 i.u./daily can be used, or larger doses of interferon can be given by intramuscular injection daily (104 - 106 i.u. per day). By 6-7 weeks, if the cat is still alive, interferon will no longer work at this dose because the cat will make antibodies against it.
To obtain human interferon-alpha (Roferon or Intron A), write a prescription for your local pharmacist. Obviously, in areas where feline interferon is available it is preferable as it is likely to have more effect than the human interferon.
Diluting human interferon
*In the UK: 2ml tubes are available from Sarstedt, supplier's ref: 72.694.006. Fax: 0116 236 66099 Tel: 0116 235 9023.
To get 104 i.u./ml put 1 x 1 million i.u. vial of Intron A or Roferon into 99ml sterile saline and divide into 1ml doses and freeze. For 105 i.u./ml use 9mls saline and proceed as above. For 106 i.u./ml use the whole vial.
Because FIP is an immune mediated disease, therapy includes suppressing the immune response, usually with glucocorticoids. Before embarking on any of the following therapies, it is essential to ensure that the diagnosis is correct, immunosuppressive drugs could markedly worsen other conditions (such as bacterial peritonitis or pleurisy). See Diagnosis of FIP Cats receiving immunosuppressants should also receive antibiotic cover to protect them against other infections. It is also important to maintain the cat's general nutrition status, by adding real meat, vitamins and antioxidants.
Prednisolone has the advantage of also being the treatment for lymphocytic cholangitis, which can be mistaken for FIP, so where the diagnosis is in doubt between FIP and lymphocytic cholangitis, prednisolone can be given anyway: the cat with lymphocytic cholangitis has a good chance of recovery, the cat with FIP unfortunately will die. Prednisolone should never be used in cats with toxoplasmosis, or leishmaniasis, neither is it safe in cases of septic peritonitis or pleurisy, which is why cytology is a very important part of effusive FIP diagnosis, as there will be many more white blood cells in the effusion of a cat with sepsis, and a good cytologist will detect the bacteria or fungi.
Dose: 2 mg/kg/sid given by mouth for 10-14 days
Prednisone is not effective in catsHugo and Reading, 2015) Meloxicam, rather than glucocorticoids, was also used in 10 experimentally-infected cats who recovered using an antiviral called GS-441524 (not yet commercially available). (Murphy et al, 2018)
Dose: 0.05 mg/kg BW, PO, q24h
Be sure to obtain the owner's consent for using a drug not licenced for cats.
Dose: 50-100mg at night. CANNOT BE USED IN PREGNANT CATS as it is teratogenic.
My go-to protocol to treat effusive FIP is to drain the effusion, give Virbagen Omega to the site of the effusion, then s/c eod after resolution of the effusion, and meloxicam or prednisolone (NOT BOTH) as the anti-inflammatory. If the anti-FCoV nucleoside analog GS-441524 (Murphy et al, 2018) becomes commercially available, that will be my go-to treatment.
Feline interferon omega: 1 million units/kg/sc/eod until recovery
Metacam (provided blood pressure and kidney function are normal): 0.05 mg/kg per os, sid.
My go-to protocol for non-effusive FIP therapy is Virbagen Omega at 100,000 units per cat per day per os and sliding doses of prednisolone. I have I have little personal experience of Polyprenyl Immunostimulant, my mind is open about its efficacy, but I would love to hear from veterinary surgeons willing to share case histories with me: contact me at draddie [at] catvirus [dot] com.
Show the cat's guardian how to withdraw 0.5mls of the diluted interferon (which now has 100,000 units of interferon per dose). Get the cat's guardian to do the syringe filling and the dosing in front of you: we vets are so used to handling syringes that we forget that most people have never handled a syringe in their lives. Some cats will take the interferon on food, but to be certain the cat gets the dose, tilt the head with the mouth closed and introduce into the commisure of the lips, wait until you see the cat swallow before releasing the head.
Remember that reconstituted, diluted Virbagen Omega lasts only up to 3 weeks in the fridge.
PPI is NOT recommended in effusive (wet) FIP.
I found the following video made by a cat's guardian, demonstrating how she doses her pet:
Vitamin B1 (thiamine)
Vitamin B complex
Multivitamins B are a good appetite stimulant and can be obtained from health food shops or chemists (I particularly like the one from Boots). Dose: paediatric dose.
Dose of vitamin E: 25-75 i.u./cat twice dailty given by mouth or in food. Vitamin E is an antioxidant.
Dose: 10mg/kg every 48-72 hrs per os.
Dose: 50 mg bid per os.
Choose from the following
(in the UK):
Remember to warn the owner
that the cat's urine could become more strong smelling with this
For AGP testing see Companion Animal Diagnostics.
Staging for effusive FIP prognosis to help you to assess whether treatment has a chance of helping or not
In this staging system shown in the video below the severity of effusive FIP can be worked out, which will give you an idea of whether or not it is worth obtaining special drugs to treat, or whether it is worthwhile continuing treating a case. Look at the parameter in the left hand column, then look at where the result of your case falls in the range, then put the score for that parameter into the next free column in the grey shaded cells. Finally work out the total score for your case. You can download the excel file here: http://www.catvirus.com/downloads.html: the total score will automatically fill in the cell at the bottom.
Interpreting the total score for your case:
While this isn’t an absolutely exact predictor, it does give a ballpark indicator of prognosis.
L-lysine should NEVER be given to a cat with FCoV infection or FIP because it is antagonistic to arginine which is essential for immune function.
Thromboxane Synthetase Inhibitors
Two cats with abdominal effusions
were treated with ozagrel hydrochloride with success (Watari et al, 1998). However, follow up studies failed to confirm the usefulness of this compound.
""Feline Infectious Peritonitis and Coronavirus" - download an ebook written for cat guardians or purchase the physical version from Amazon.
The chapters are:
1. Everything you need to know when your cat has been diagnosed with FIP
........(This download will open up in a new page as a word document.)
2. Everything you need to know about treating a cat with FIP
...... Download a current FIP treatment sheet from the Downloads menu to take with you to your veterinary surgeon.
3. Preventing your other cats or kittens from developing FIP
4. Everything you need to know about getting another cat or kitten
5. Everything you need to know if your cat or kitten is diagnosed as having diarrhoea caused by FCoV
6. Everything you need to know if you work in a rescue shelter or boarding cattery
7. FCoV/FIP prevention in trap, neuter, return (TNR) programs
8. Everything you need to know if you keep a lot (over 6) pet cats, or have a cat sanctuary or colony
9. Everything you need to know if you are a cat breeder
10. What you can do to help fight FIP
11. Everything you need to know to find more information
I should very much like to conduct a clinical trial on the effectiveness of various treatments for FIP, but unfortunately don't have the funding to do so. I'd like to thank Mr Wayne Carr and all the other donors to the Angelica FIP trust, to the catvirus subscribers and the EndFIP group, whose generous donations made preliminary investigations possible. Enormous thanks go to the human families of cats who have had FIP, who have generously given of their time, and samples from their cats, to make my research possible and a BIG THANK YOU also to all the veterinary surgeons who have contributed to my studies.
Addie D.D., 2004 Feline Infectious Peritonitis. Veterinary Interferon Handbook. Ed: Karine de Mari. Virbac. 108-117
Addie D.D.2008 Feline infectious peritonitis – therapy and prevention. Kirk’s Current Veterinary Therapy XIV Edited by: John D. Bonagura, DVM, MS, DACVIM, David C. Twedt, DVM, DACVIM. Saunders, Elsevier.1295 – 1299
Addie, D.D.. Feline coronavirus. 2012 Infectious Diseases of the Dog and Cat. 4th edition. Editor: Greene, Craig. Published by W.B. Saunders Elsevier Company, 11830 Westline Industrial Drive, St. Louis, Missouri 63146, USA. ISBN 978-1-4160-6130-4 92-108
Hartmann K, Ritz S. 2008 Treatment of cats with feline infectious peritonitis. Vet Immunol Immunopathol. 123(1-2):172-5.
Legendre AM, Bartges JW. 2009 Effect of Polyprenyl Immunostimulant on the survival times of three cats with the dry form of feline infectious peritonitis. J Feline Med Surg. 11 624-626
Legendre AM, Kuritz T, Galyon G, Baylor VM, Heidel RE. 2017 Polyprenyl Immunostimulant Treatment of Cats with Presumptive Non-Effusive Feline Infectious Peritonitis In a Field Study. Front Vet Sci. 4:7.
Maunder CL, Day MJ, Hibbert A, Steiner JM, Suchodolski JS, Hall EJ. 2012
Murphy BG, Perron M, Murakami E, Bauer K, Park Y, Eckstrand C, Liepnieks M, Pedersen NC. The nucleoside analog GS-441524 strongly inhibits feline infectious peritonitis (FIP) virus in tissue culture and experimental cat infection studies. Vet Microbiol. 2018 Jun;219:226-233.
O'Brien, DP & Packer, RA (2010) Metabolic encephalopathy: organic acidurias. In August, JR (Ed): Consultations in feline internal medicine. Vol 6. Elsevier Saunders, Philadelphia. pp:595
Pedersen NC, Kim Y, Liu H, Galasiti Kankanamalage AC, Eckstrand C, Groutas WC, Bannasch M, Meadows JM, Chang KO. Efficacy of a 3C-like protease inhibitor in treating various forms of acquired feline infectious peritonitis. J Feline Med Surg. 2017 Sep 1:1098612X17729626.
Simpson KW, John Fyfe, Angelyn Cornetta, Amy Sachs, Dalit Strauss-Ayali, Stephen V. Lamb, Thomas J. Reimers 2001 Subnormal Concentrations of Serum Cobalamin (Vitamin B12) in Cats with Gastrointestinal Disease J Vet Intern Med 15:26–32
Swann JW, Szladovits B, Glanemann B: Demographic Characteristics, Survival and Prognostic Factors for Mortality in Cats with Primary Immune-Mediated Hemolytic Anemia. Journal of Veterinary Internal Medicine 2016, 30:147-156.
Takano T, Hohdatsu T, Hashida Y, Kaneko Y, Tanabe M, Koyama H. 2007b A "possible" involvement of TNF-alpha in apoptosis induction in peripheral blood lymphocytes of cats with feline infectious peritonitis. Vet Microbiol. 119(2-4):121-31
Takano T, Azuma N, Satoh M, Toda A, Hashida Y, Satoh R, Hohdatsu T. 2009 Neutrophil survival factors (TNF-alpha, GM-CSF, and G-CSF) produced by macrophages in cats infected with feline infectious peritonitis virus contribute to the pathogenesis of granulomatous lesions. Arch Virol. 154(5):775-81.
Watari T, Kaneshima T, Tsujimoto H, Ono K, Hasegawa A. 1998 Effect of thromboxane synthetase inhibitor on feline infectious peritonitis in cats. J Vet Med Sci. 60(5):657-9.
Weiss Richard C. 1994 Feline
Infectious Peritonitis Virus: Advances in Therapy and Control in
Consultations in Feline Internal Medicine
2. Edited by John R. August. Published by W.B. Saunders Company.
Harcourt Brace Jovanovich, Inc., The Curtis Center, Independence
Square West, Philadelphia, PA 19106. pages 3-12
Dr Diane D. Addie 28 May 2018