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If you have opened this FIP (feline infectious peritonitis) treatment manual, you probably have a small feline patient with FIP at home. This manual will show you everything you will need for treatment, and will help you understand the basic rules of treatment and answer basic questions related to the disease and its treatment.

If you are experiencing stress because your cat is sick with suspected FIP, or has just been diagnosed, pay attention to the chapters that are relevant to you. It is not necessary to swallow all the information immediately from the region. Give yourself time and peace to understand everything. Don't be afraid of anything and think about the fact that you are already on a well-trodden path, that many others have done it before you, and that's why you can definitely do it too.

1. Disease and its diagnosis

If your cat has FIP, it is likely that she is apathetic, tired, loses her appetite, loses weight, has a fever, the mucous membranes of the mouth and lids may be pale (anemia) or yellow (icterus), she is either without effusion or has an abdominal / chest effusion, or both at the same time. May have ocular or neurological symptoms.

1.1. If your cat is suspected of having FIP, what should you ask the vet for?

Diagnostic minimum:

  1. clinical examination, sonographic examination of the abdomen, x-ray of the chest in inhalation
  2. hematological examination including differential budget of white blood cells and biochemical examination including albumin, total protein, bilirubin and ions
  3. wet FIP – PCR and Rivalt's test from an effusion sample (careful, if it is an abdominal effusion, take only a sample, never all; for thoracic effusion, on the contrary)/dry FIP – if a biopsy, PCR or immunohistochemical examination of a mesenteric lymph node sample is possible
  4. Electrophoresis of serum proteins, or SAA – serum amyloid A

Share the results and the report from the doctor in the group that helps you with FIP treatment.

1.2. What form of illness does your cat have?

Wet FIP – especially in kittens and young animals up to about 2 years of age; the onset of the disease is massive – from full health comes fever, apathy, loss of interest in food; soon an effusion appears in the peritoneum (abdomen) or pleural area (chest), or both at the same time; this form lasts about 2–3 weeks from the first symptoms, but sometimes even less, than death follows in case of no treatment.

Dry FIP – the onset is gradual, the first symptoms often go unnoticed by the owner – the animal gradually loses activity, interest and appetite; the quality of the fur deteriorates, the animal shows signs of emaciation – the spine, ribs and coccyx protrude; dehydration, advanced anemia/jaundice (icterus); in the final phase, there is often an effusion, just like in the wet form! – be careful not to confuse with wet FIP, which is treated at a lower dosage; the dry form lasts for weeks to months. Sono will demonstrate the involvement of organs and abdominal nodes.

Ocular FIP – occurs on the basis of dry FIP + bloody discharge in the eye, clouding of the eye, inflammatory changes in the eye; unevenly dilated pupils (there is usually a transition to the neuro form here!); dull (matted) reflection of the eye fundus.

Neurological FIP – emergence on the basis of dry FIP + balance disorder, staggering, convulsions, unnatural tilting of the head, inability to jump to elevated places, enlargement of pupils not responding to light, blindness...

WARNING! – just as with the dry form, as well as with the ocular and neurological, an effusion may appear in the abdominal and/or chest cavity in the final phase of the disease. In such a case, it is not wet FIP and it is necessary to use the dosage corresponding to the original form of FIP (dry/ocular/neuro).

If your cat has lost a significant amount of weight, but at the same time has a discharge in the abdomen or chest, this means that she has been ill for a long time and therefore that it is a dry form of FIP with discharge. Here it is necessary to treat at a higher dosage than primary moist FIP. The same is the case with apparently wet FIP in very small kittens, so-called stunted growth, when their weight does not correspond to their age. In these cases, in most cases, the presence of fluid in the abdomen (abdomen) makes sonographic examination impossible for a typical finding in dry FIP (enlarged mesenteric nodes, granulomas on the liver...)

In these cases, we also recommend checking whether ocular or neurological symptoms are no longer developing - a longer course of the disease carries the risk of virus penetration into the CNS.

More about the diagnosis of individual forms here: FIP diagnostics – FIP Warriors CZ/SK ®

2. We start the treatment

If your cat is breathing heavily or rapidly (more than approx. 30-35 breaths per minute), has a low temperature (below 37 °C), does not respond or is unable to move, immediately seek first aid from a veterinarian - for survival, it will be necessary at the same time as treatment above all, ensuring life support (infusion, oxygen, warming box, transfusion...)

Attention - if the cat is breathing heavily, it has probably developed a chest effusion and it must be quickly suctioned at the vet (after an X-ray examination), otherwise there is a risk of death.

Important notice!

If your cat is in a poor nutritional state and does not accept food, pay close attention to the chapter on the need for forced feeding of sick cats (and, of course, consult a veterinarian).

More here: About the necessity of feeding sick cats - FIP Warriors CZ/SK ®

2.1. Provision of medicines

If you are in a Facebook group dedicated to the treatment of FIP, you probably already have the medication secured. If you found this manual on the web FIP Warriors CZ / SK and you need advice on securing medicine, but you are not yet in the Facebook group, join the group FIP Warriors CZ/SK ? | Facebook. Attention - do not contact the admins directly on the group, but post a post stating where you are from - there is a chance that someone in your area is treating and will provide you with the medicine for the first few days.

Another possibility is the direct purchase of the medicine on the Internet, but here you have to take into account a longer delivery time, which, especially in the case of wet FIP, can be fatal for the cat. Therefore, even in such a case, we recommend securing at least a starting (bridging) dose in the Facebook group - in addition to the admin of the group, other healers can help you.

2.2. Types and forms of medicine - which one to choose

GS441524 is still the drug of first choice in FIP therapy. There are many brands and concentrations on the market, the form of the drug mainly as an injection solution or tablets, or capsules, and less common, for example, sweepers (pillows to dissolve on the palate).

From 2021, treatment with molnupiravir (EIDD) is also possible, but it is mainly used for the treatment of relapses, when partial or complete resistance to GS441524 is suspected. Molnupiravir must always be administered twice a day, after 12 hours.


Injection solution

Application: it is applied subcutaneously using a syringe; the advantage is approx. 100% absorbability - if you plan to treat with tablets, but the cat is in a serious condition, we recommend injectable treatment until she is stabilized (approx. min. 1–2 weeks)

Who it is suitable for: all forms of FIP

Packaging: injection solutions are distributed in vials with a volume of approx. 5–6 ml (according to the brand) and are on the market in various concentrations (mostly 15–20 mg/ml)

How to store: solutions are best kept in the cold (refrigerator)

Note: treatment with injection solutions is usually more cost-effective than tablet form

What to watch out for: if the cat has a pleural effusion or severe anemia and is breathing rapidly or heavily, it is a good idea to get veterinary help first - the injection can be painful for some cats and in the case of circulatory problems (very impaired breathing, strained heart) could in extreme cases circulatory collapse from shock.


Application: administered orally, whole (or halved, quartered - depending on the dose); be careful - do not crush or mix with water - the cat could spit out part of the medicine. Serve on an empty stomach or with some food; after administration, check that the cat has not vomited the tablets within the next 2 hours, if so, administer the dose again

Restrictions - for whom it is not suitable: if the cat suffers from diarrhea, constipation, vomiting, or has slowed peristalsis or suffers from malabsorption (e.g. as a result of prolonged starvation), the absorption of the tablet in the digestive tract may be reduced and there is a risk that the cat will not receive a sufficient effective dose substances.

Note: if the cat is not at risk of limited absorption, it can be treated with tablets from the very beginning, especially if the cat accepts food and excretes normally (the effect of the drug can be verified by the onset of improvement on the first to second day after the first dose); however, if the condition is serious or the cat's condition does not improve, it is advisable to start with the injectable form and only switch to tablets after the condition has stabilized.


You can find out more about molnupiravir treatment here: EIDD-2801 (Molnupiravir) – FIP Warriors CZ/SK ®

2.3. Determination of dosage and calculation of daily dose


Correct dosage is a prerequisite for successful treatment while simultaneously minimizing the risk of relapse (disease flare-up). This can happen if the virus is not sufficiently controlled during the treatment, and it is thus given room to penetrate the CNS, if it was not present there before.

General dosage recommendation (expressed in the amount of GS in mg/kg of the cat's weight):

FIP typeDosage
Wet FIP (kittens and cats under 2 years of age)6 mg/kg (injection)
8 mg/kg (tablets)
Dry FIP without effusion / with effusion8 mg / kg
Ocular FIP10 mg / kg
Neurological FIP12 mg / kg
Relapse12-15 mg / kg

The tool will help you determine the correct dosage Determination of dosage according to FIP symptoms – FIP Warriors CZ/SK ®, where, among other things, it is also possible to distinguish whether it is a primary wet FIP or a dry form with effusion.

ATTENTION - if your cat has unevenly dilated pupils, or dilated pupils that do not react to light, it is rather a neurological form, and we therefore recommend treating her with the dosage for the neuro form. In the same way, it is necessary to distinguish whether some of the symptoms listed in the neuro section, such as weakness of the hind legs, inability to jump to a high place, are actually related to the nervous system, or whether it is a symptom of general weakness. In case of doubt, solve this question with your veterinarian, who can perform, for example, a basic neurological examination, or refer you to a specialist. Again, here too, it is necessary not to underestimate if it could be a neuro form - this is the only way to reduce the risk of relapse and successfully cure the cat.

Calculation of the daily dose

If you have already determined the dosage, you can proceed to the calculation of the daily dose. Perform the calculation using the tool Dose calculator – FIP Warriors CZ/SK ®.

  • Choose the type of medicine (GS and injection form by default)
  • Enter your current weight (always round to the nearest 10 dkg up!)
  • Enter the dosage according to the FIP form in mg/kg (see chapter above)
  • Select the drug concentration (in mg/ml)

In the yellow window, you will get the amount of medicine for the daily dose

Note: in case you find yourself without internet access, you can also use the following formula for the calculation:

i = m * d / c

i: final dose for injection [ml]
m: weight of the cat [kg]
d: dosage of the active substance (GS441524) for the given type of FIP [mg/kg]
c: concentration [mg/ml] or GS content in mg in one tablet

(ATTENTION: For tablets, do not forget about 50% bioavailability of the active substance compared to injections. It is necessary to have information about whether the GS content of the tablet is real or so-called equivalent.)


The weight of the cat is 2kg,
dosage of GS for a given type of FIP is 6mg / kg,
concentration of the injection solution is 15mg / ml.

We substitute in the formula and get:

i = 2 * 6/15 = 0.8 ml

WARNING! Weigh the kitten at least 2 times a week, and if the weight increases, recalculate the daily dose on the GS calculator. Always round the weight up to the nearest 10 dkg.

Sample calculation on the GS calculator (3 kg, wet form, injection 16.9 mg/ml/tablets 16 mg):

2.4 Application of the drug

Injection solution – always use a new sterile syringe and injection needle for each administration! Do not disinfect the injection site; the medicine is applied subcutaneously, in the subcutaneous layer (ie between the skin and the muscle) - see picture; after giving the injection, you can lightly wipe the site with a tissue to check that no medicine has leaked out

ATTENTION - in the event that the medicine leaks from the skin into the coat (within approx. 30 minutes after the injection), it is necessary to inject the appropriate amount so that the cat receives the entire dose

If you are administering a larger amount of the drug, you can divide the application into 2-3 places, or the daily dose can be divided into two halves with the application after 12 hours.

Alternate injection sites every day (see picture)

How to apply: the standard is a 2 ml syringe, green needle 0.8x25mm (or 0.8x40mm) (for tiny kittens, we recommend a 1 ml syringe, it is more accurate)        

If a jelly-like lump forms under the skin, avoid applying to the area on the following days until the lump is absorbed; in case a lesion forms on the skin (scab or open wound), use colloidal silver. A lesion may be a sign that the drug was applied too shallowly.

The injection is usually administered once a day, with an interval of 24 hours, in the case of the neuro form (larger volume of the drug) it is possible to divide the dose every 12 hours.

Demonstration of how to give a cat a subcutaneous injection (see method 1 and 2): How to inject a cat - FIP Warriors CZ/SK ®

Video sample: (43) How to Give Subcutaneous Injection to your Cat at Home - YouTube


Put the tablet by hand or using the tablet feeder on the base of the cat's tongue or throw it straight into the esophagus (the cat must not inhale the tablet, of course), wait until it swallows it, or give the cat a little water from the syringe

Check that the cat has not spit the tablet out of the throat, or that it is not stuck to the gums or hidden under the tongue; after administering the tablet, watch for approx. 2 hours that the cat has not vomited the dose of tablets - if this happens, give the dose again.

Tablets can be given on an empty stomach, with a little food or normally with food - each cat is comfortable with something different, or consult with others who treat on the fb group.

If your cat has a dosage of 10 mg or more (ocular, neuro, severe dryness), or if she reacts worse or has a dose of more tablets (e.g. 3) due to her higher weight (limited ability to absorb tablets), divide the daily dose into two, e.g. morning and evening , with a lower dosage 1 x a day every 24 hours.

Example of tablet administration: 6 Ways to Give a Cat a Pill (wikiHow Pet)

WARNING! – if you believe that your cat does not respond adequately to the treatment with tablets, i.e. the improvement is very slow or the condition stagnates or worsens, and at the same time it has been ruled out that there is some secondary problem behind her condition besides FIP (e.g. pancreatitis, bacterial infection, etc.) , you need to react quickly and ensure the transition to temporary administration of injections!

WARNING! – outdoor or semi-outdoor cats may refuse to go home regularly after their condition has improved due to fear of handling and applying the medicine – therefore we recommend not letting all treated cats outside during treatment and during post-treatment – this will prevent during treatment not only the risk of the cat missing one or more doses, but also at the same time, that any worsening of the condition will not be attributable to something the cat was exposed to during her stay outside (infection, poisoning, internal injuries,...) and which may show similar symptoms (apathy, loss of appetite,...)

2.5. What to buy - tools and instructions  

What will you need during treatment?

  • digital scale (for cats up to 3 kg and of small height, a larger kitchen scale is sufficient, we generally recommend a scale for babies (it is accurate and the surface allows weighing even larger cats) - we recommend especially with regard to the seriousness of the situation and the overall investment in treatment, where by determining the correct dose according to the current scales can be the difference between cure and relapse or even life and death, be careful - weighing on a personal scale, including the method of a person with a cat in his arms and a person without a cat in his arms, is very inaccurate, we do not recommend it!
  • tailor's tape measure or string – in the case of moist FIP with abdominal (peritoneal) effusion, it is advisable to measure the circumference of the abdomen over the widest point regularly until the fluid disappears, ideally daily, and write it down regularly.
  • digital thermometer – a digital high-speed thermometer with a flexible tip (in case the cat was treated for a fever, and to check the temperature when you notice that your cat does not feel well, is apathetic, breathes poorly, does not react (the normal temperature of a cat is approx. 37 .5 - 39°C; the temperature may rise slightly under stress; above 39.5°C is a fever; at a temperature below 37°C it is hypothermia - in both cases, contact the veterinarian.
  • notebook or notepad – during treatment, we recommend regularly writing down information about the cat's state of health, especially weight, temperature, abdominal circumference in the case of a wet form of FIP with peritoneal effusion (until the effusion disappears), activity, appetite, in case of excretion problems or other difficulties, their onset and course , and the amount of medication administered on a given day – these notes can be very helpful when, for example, the health condition worsens, or any other problem arises that deserves attention in connection with the treatment of FIP (of course, records can also be kept in electronic form).
  • supply of syringes and needles in the case of treatment with injection solutions - syringes with a volume of 2 ml (for cats with a daily dose between 2 and 3 ml, we recommend 2 ml syringes with markings up to 3 ml); cats weighing up to 2.5 kg and wet FIP (daily dose up to 1 ml) syringe 1 ml; needles green 0.8 x 25 mm, or 0.8 x 40 mm
  • tablet feeder with silicone tip (when treated with tablets) – not necessary, it is suitable for cats that refuse to accept a tablet given by hand

2.6 Support during treatment

Hepatoprotective agents – the treatment may put a slight strain on the liver during treatment (temporarily), therefore it is recommended to administer preparations to support liver activity (hepatoprotectors) throughout the treatment period, see Liver – FIP Warriors CZ/SK ®

Consult with your veterinarian whether your cat has another problem in addition to FIP (e.g. impaired kidney function, inflammation, etc.) and get advice from him on the appropriate therapy (diet / medication / support products,...)

Provide your cat with plenty of water during treatment and make sure she drinks well.

Diet: if your cat does not have any dietary restrictions (e.g. a veterinary diet for a specific health problem), feed her the normal diet she was used to before the illness - most cats will regain their full appetite within the first few days of treatment. If the kitten is weak, give it a diet for convalescents or other support after consultation with the veterinarian. If your cat has not eaten for a long time or if it takes a long time to start eating due to a specific health problem, proceed according to the instructions - see "important notice" at the beginning of chapter 2.

2.7. Completing the statistical treatment questionnaire

Once you start treatment, fill out the questionnaire Statistics on the treatment of FIP in the Czech Republic/SR – FIP Warriors CZ/SK ®. Why fill in the questionnaire?

In the beginning, you are naturally interested in how successful the treatment is, whether the drugs you are treating with are of high quality and proven, whether the disease will not return, whether it is only a matter of prolonging life by a few months by suppressing the virus and not a full cure, etc. These questions can be answered by statistics, which are made up of the answers of those who treated before you and which you are now following in your efforts to cure your feline friend. At the same time, you contribute to an overview of risk factors, frequency of occurrence according to age, sex, breed, probable triggers of the disease, etc.

For others, we will be able to count on you to provide medication or informational support in the group. It is no less important that by filling out the questionnaire at the beginning of the treatment, you become a contact for possible acute cases in your area and can thus save the life of a cat - you may have experienced this yourself at the beginning of the treatment. The group desperately needs this help from you, because the more mutual help, the more lives saved.

In conclusion, we remind you that filling out the statistical questionnaire for the treated cat is one of the rules of the group, which provides you with maximum information and other support in exchange for this data.

2.8. Veterinary checks

During the treatment, it is necessary to undergo regular veterinary checks, when the doctor evaluates the overall clinical condition, performs a control sonographic examination of the abdominal cavity, possibly a control X-ray, and performs control blood tests. Based on them, they will evaluate whether the results improve with the course of treatment. Take the results and the report from the control examination with you and then share them in the fb group under which you are treating your cat. In case of unsatisfactory results or if the clinical condition does not improve, it is necessary to consider changing the form of treatment (from tablets to injections) or dosage.

What results to demand: essentially the same blood analysis as at the beginning of the treatment is carried out, i.e. hematology including the differential budget of white blood cells, biochemistry including albumin, total protein, bilirubin. During the final examination, add electrophoresis of serum proteins, or SAA – serum amyloid A.

How often to check and when to stop treatment? Carry out the check after the 4th and 8th week of treatment, and then in the 12th week (or at the turn of the 11th/12th week) - ATTENTION, do not end the treatment at the end of 12 weeks (84 days), but only after evaluating the final results and the overall status.

More here: FIP treatment timeline (FIP Warriors CZ/SK ®)

3. What to expect from the treatment?

(Description of a typical course of treatment)

3.1. Procedure for improving the condition

Your cat should begin to improve very quickly after the start of the treatment - usually the first improvement is observed approximately 12 to 24 hours after the first administered dose. If the cat's condition does not improve within 1-3 days, or if it worsens, seek veterinary help immediately, and then inform the admin of the FIP group under which you are treating.

In such a case, it is necessary:

  1. Veterinarian
    • to resolve whether there is some secondary/associated problem behind the condition, e.g. bacterial infection, pancreatitis, too strong anemia, etc. – unfortunately, many veterinarians often overlook the related problem when initially diagnosing FIP or attribute it purely to FIP; if the condition was too serious at the beginning of the treatment, temporary veterinary support may be necessary to stabilize the condition - infusion therapy, oxygen box, heating...
    • if it is a treatment for a case where not all diagnostic options have been used and there is a possibility of a differential diagnosis, it is necessary to diagnose - see chapter Step 1 - diagnosis - IT MAY BE ANOTHER DISEASE and your veterinarian did not determine the diagnosis correctly!
  2. Consider whether the dosage is really set correctly - this is mainly about wet versus dry FIP with effusion - you can check it on the click-out tool (see chapter 2.3 of the manual)
  3. When treating with tablets, it is necessary to consider whether the cat absorbs the tablets well, if the condition is bad and stagnates or worsens, we recommend temporarily switching to an injectable form of treatment
  4. In case of resistance to treatment with GS – treatment with GS is still the first-line treatment, but if resistance to treatment occurs in some very rare cases, treatment with molnupiravir (EIDD) can be switched; how to recognize resistance? – the cat has a veterinarian-confirmed diagnosis of FIP, see Step 1 of the manual, an aggravating health problem has been excluded or resolved, but does not respond even after increasing the dosage and changing the brand or form of the drug

WARNING! – In some cases, cats with FIP have persistent constipation, and this is sometimes the reason why they do not have an appetite despite the use of treatment – while the return of appetite is one of the indicators that the treatment is successful. Therefore, in order to be able to distinguish whether constipation is behind the loss of appetite, or the cat is not responding to the treatment properly, the problem of constipation must be solved - visit a veterinarian, and in case of constipation, follow the instructions (e.g. administration of lactulose, probiotics, heating and massage of the abdomen, etc.).


Fluid in wet FIP/dry FIP with effusion should begin to be absorbed during the first week of treatment. It is sometimes observed that the volume of fluid may increase slightly during the first few days, but this condition should be gradually adjusted, and if this happens, the clinical condition of the cat must not worsen at the same time.

In the event that the liquid is not absorbed even during the first month (the usual time until which most cats absorb the liquid), or it increases without the cat's condition worsening, we recommend having a sample of the effusion taken again in order to determine its origin ( e.g. cytological analysis) – sometimes it can be concurrent with e.g. pancreatitis or inflammation of the liver or another secondary disease.


If your cat has a neurological or ocular form of FIP, in most cases some change towards the correction of the condition is observed within about 3 days from the start of treatment. If this does not happen, consult the situation with the FIP group and your veterinarian. If the cat has become blind due to neurological FIP (ie it is not an ocular form, but the optic nerve or a center in the brain is affected), it may take several days for vision to return. However, if the vision does not return even after a week of treatment, we recommend consulting the situation with a specialist (neurologist, ophthalmologist). It goes without saying that the form of treatment must first be changed (if it is a tablet, switch to an injectable; then increase the dosage, and if it is certain that it is FIP, but the response to GS is not adequate, then a switch to an alternative drug, i.e. molnupiravir (e.g. Lagevrio )).


During the treatment, it is recommended to undergo 3 check-ups – after 4 weeks, after 8 weeks and in the 12th week. Already after 4 weeks of treatment, it should be observed that the ratio of neutrophils to lymphocytes has improved (if the cat had neutrophilia and lymphopenia at the beginning of treatment, neutrophils should decrease and lymphocytes, on the contrary, should rise), the red blood count should be adjusted if anemia was present (ie hemoglobin and hematocrit should increase to normal), bilirubin should return to normal (if it was elevated), and globulin should decrease and albumin should increase. If the globulins do not decrease after 4 and possibly 8 weeks of treatment, it is necessary to consider increasing the dosage for the remaining time of treatment, if the condition persists even at the end of the treatment, it is necessary to consider an extension with a further increase in dosage.

3.2. Termination of treatment

The duration of treatment usually lasts 12 weeks (determined according to a clinical study by Dr. Pedersen, see FIP Warriors CZ / SK), but it NEVER ends with the mere expiration of the treatment period thus determined. How and when to stop the treatment?

  1. The kitten is in very good condition, shows no signs of FIP, and at the same time:
  2. The kitten has gained its original weight before the disease (in the case of a kitten, it has grown to a weight corresponding to normal individuals of its age, breed and sex), and at the same time:
  3. The final veterinary check showed that all blood values, monitored during treatment, are within the norm and in mutual proportions corresponding to a healthy cat:
    • The red blood cell is normal, the cat shows no signs of anemia
    • White blood cells – mild neutropenia, a good sign is mild lymphocytosis
    • Proteins: albumin in the norm (rather above the middle of the norm), reduced globulin, ideal alb/glob ratio close to 1 or higher
    • Bilirubin – normal
    • In case of an increase in liver or kidney values above the norm, the situation should be consulted with a veterinarian and appropriate measures should be chosen (supplement support, drugs, diet,...), followed by a check to see if the condition has improved and it was only a temporary deterioration as a result of the treatment

4. Follow-up period – Posttreatment

4.1. What is posttreatment

The follow-up period (post-treatment) awaits you at the moment when you have finished the treatment (see chapter 2.8 of the manual). These are the following 12 weeks, which are used to observe and evaluate whether the treatment went well. During this period, avoid exposing the cat to stress, the risk of transmission of infection (just as it applies to the treatment period, we also recommend not letting outdoor and semi-outdoor cats outside during the post-treatment), do not plan surgical procedures (if they are not absolutely necessary). We also recommend supporting immunity and, in the event that the cat had impaired liver values at the end of the treatment, to continue administering hepatoprotectors. The period of 12 weeks after the treatment is critical for evaluating whether the treatment was successful or whether a relapse did not occur - it usually manifests itself neurologically.

4.2. How to recognize relapse, risks and frequency of occurrence

The kitten loses activity and interest in food, fever may occur; neurological symptoms usually develop gradually - problems with walking, coordination of movements, incontinence, etc. In such a case, it is necessary to immediately seek the help of a veterinarian to rule out other causes. In the event that it really is a relapse, it is necessary to immediately start a new GS treatment in an increased dosage (min. 12 mg for a relapse after wet/dry FIP and min. 15 mg for a relapse after ocular/neuro FIP) or relapse treatment with an alternative drug (molnupiravir). Because even relapse is fully curable in most cases.

If you suspect a relapse, contact your veterinarian and your home FIP group immediately.

Risks of relapse and frequency of relapse

We managed to significantly reduce the frequency of relapses in our group, the incidence is around 2 % out of the treated number, and this most often occurs when it is proven that the owner underestimated some of the symptoms that the cat showed at the beginning, that is, there was an error in determining the form of FIP and adequate dosage, or the treatment did not proceed as it should (missing doses, irregularity in weight control and subsequent increase of the daily dose,...)

The basis of success is therefore:

  • correct determination of dosage depending on the correctly determined type of FIP, see chapter 1.2 and 2.3 of the manual.
  • correct application of the drug, regularity, passing veterinary checks

Why not let the cat outside during posttreatment?

During this period, the cat may be susceptible to bacterial and viral infections (immunity may be reduced after treatment), so it is good not to expose the cat to influences that could endanger it. If, for example, she were to become infected with something or eat something inappropriate outside, you would not be able to distinguish quickly and in time what is happening to her. Whether it is a relapse or another problem. Attention - in case of relapse, the blood values are often normal, because the virus is hidden in the central nervous system!

Did you successfully complete posttreatment? Congratulations! Your kitty is cured. You can look forward to more years together.

(You can write a review of the medicine you were treated with here: Medicines – FIP Warriors CZ/SK ®)

5. Frequently asked questions - FAQ

There are many questions related to the treatment of FIP and the disease itself - you can find the most important ones at this link: Frequently asked questions – FIP Warriors CZ/SK ®

We recommend going through them thoroughly. If you can't find an answer to your question even there, try asking it on the fb group or searching in keywords both on the group and on the website, most of the questions about treatment have already been asked and answered at some point.

Here are just a few basic things that you are most often asked about:

  1. Rapid test for FIP - this is not a FIP test, but a test to determine the presence of antibodies to the common intestinal coronavirus (FCs), this test is positive for most cats (regardless of whether they have FIP or not) and it is not proof of FIP disease!
  2. Infectivity – it is generally believed that, unlike FeLV and FIV, FIP is not transmissible, because it is an individual mutation; most owners of cats with FIP had a sick cat among healthy cats without others getting sick; in some cases (shelters, large groups of cats), however, the disease has occurred several times in several individuals (that it is transmission, however, except for one case, has not been investigated and proven)
  3. Immunity support - we do not recommend during treatment, unless it is necessary for another ongoing health problem (eg FeLV), support immunity only after treatment.
  4. Castration – if it is necessary to castrate the cat, it is recommended to plan it for approx. 60 to 65 days of treatment, not for the post-treatment period. It is advisable that after neutering, the cat should be covered with treatment for approximately 2 to 3 weeks

A few words at the end

This manual may have answered some of your questions, you can get more information on the website or in your home fb FIP group - don't be afraid to ask, search, connect with those who have experience. Spread your experience so that as many people as possible in your area, including your veterinarian, learn that the treatment works. You can thus help save many cats' lives. 

The fight with FIP may not be easy for everyone, but it is worth it - for the sake of that little feline friend who relies on you, and for whom it is the only chance to survive with this diagnosis.

So keep your head up and go for it with courage! You can definitely do it!