What Is the Best Treatment for FIP in Cats in the UK?

Key takeaway: The best treatment for Feline Infectious Peritonitis (FIP) in cats in the UK is GS-441524 antiviral therapy delivered over an 84-day protocol under veterinary supervision. GS-441524 is the antiviral at the core of modern FIP treatment, with a 92% success rate reported by UC Davis (Pedersen, 2019). The right product, dose, and route depend on which of the four forms of FIP your cat has, so the plan should always be set with your veterinarian.

What Is the Best Treatment for FIP in Cats in the UK?

What is the best treatment for FIP in cats in the UK?

The best treatment for FIP in the UK is a full course of GS-441524, the antiviral that sits at the centre of modern FIP care. Evidence shows GS-441524 monotherapy achieved a 92% success rate in the UC Davis field study (Pedersen, 2019), and a standard course runs 84 days under veterinary supervision. CureFIP has supported a network of more than 100,000 cats treated since 2019, and our role is to be clear about what the data shows and what it does not.

FIP was historically one of the most feared diagnoses in feline medicine. Today, with GS-441524 and a structured 84-day protocol, remission is a realistic goal for many cats. The treatment you choose should match the form of FIP, your cat's weight, and your veterinarian's assessment.

What causes FIP and why does early treatment matter?

FIP is caused by a mutation of feline coronavirus that allows the virus to infect immune cells and spread through the body. It matters to start treatment early because FIP progresses quickly, and the form it takes shapes the dose and the route your veterinarian will recommend. Bloodwork, imaging, fluid analysis, and clinical signs all help confirm the diagnosis before treatment begins.

FIP takes four forms, wet, dry, ocular, and neurological, and each shapes the treatment plan. The sections below mirror the four-row dosing structure used for GS-441524 injectables so the symptoms and the dosing stay aligned.

Wet (effusive) FIP

Wet FIP is the effusive form, marked by fluid building up in the abdomen or chest. Cats with wet FIP often show a swollen belly, laboured breathing, lethargy, and weight loss despite a distended abdomen. With CureFIP GS-441524 injectables, the catalog dose for wet FIP is 6 mg/kg given as one subcutaneous injection per day, 7 days a week, for 84 days. Confirm your cat's exact dose with your veterinarian.

Dry (non-effusive) FIP

Dry FIP is the non-effusive form, where inflammatory lesions form in organs without significant fluid build-up. Signs can be vaguer than wet FIP and include persistent fever, weight loss, poor appetite, and jaundice. With CureFIP GS-441524 injectables, the catalog dose for dry FIP is 8 mg/kg given as one subcutaneous injection per day, 7 days a week, for 84 days. Your veterinarian will confirm the precise dose for your cat.

Ocular FIP

Ocular FIP affects the eyes and can appear alongside the dry form. Signs include colour changes in the iris, cloudiness, inflammation inside the eye, and changes to vision. With CureFIP GS-441524 injectables, the catalog dose for ocular FIP is 10 mg/kg given as one subcutaneous injection per day, 7 days a week, for 84 days. Because ocular involvement signals deeper penetration is needed, confirm the dose with your veterinarian.

Neurological FIP

Neurological FIP involves the brain and spinal cord and is the most demanding form to treat because the antiviral must cross the blood-brain barrier. Signs include wobbliness, seizures, behaviour changes, and partial paralysis. With CureFIP GS-441524 injectables, the catalog dose for neurological FIP is 10 mg/kg given as one subcutaneous injection per day, 7 days a week, for 84 days. Neurological cases require close veterinary oversight throughout.

How does the GS-441524 dosing work for each form of FIP?

GS-441524 injectable dosing is set by the form of FIP, with one subcutaneous injection per day, every day, for 84 days. The table below uses the dosing figures exactly as listed in the CureFIP catalog. Your veterinarian calculates the daily volume from your cat's weight and the product concentration.

FIP form

Catalog dose

Schedule

Duration

Wet / effusive

6 mg/kg

1 subcutaneous injection per day, 7 days/week

84 days

Dry / non-effusive

8 mg/kg

1 subcutaneous injection per day, 7 days/week

84 days

Ocular

10 mg/kg

1 subcutaneous injection per day, 7 days/week

84 days

Neurological

10 mg/kg

1 subcutaneous injection per day, 7 days/week

84 days

Reference: Pedersen et al., UC Davis (PMC6435921). Never adjust a dose on your own. The figures above are starting points your veterinarian will confirm and may revise based on bloodwork and response.

Which CureFIP product is right for my cat?

The right CureFIP product depends on whether your cat is treated by injection or by oral capsule, and on your cat's weight and FIP form. CureFIP offers three GS-441524 injectable strengths and an oral dual antiviral option. Prices below are listed in EUR exactly as shown in the catalog.

Product

Strength

Volume

Price

CureFIP™ GS-441524 Injectable 20mg/ml

20 mg/ml

8ml, 10ml

€79.00

CureFIP™ GS-441524 Injectable 30mg/ml

30 mg/ml

8ml, 10ml

€89.00

Cure FIP Antiviral 40mg/ml

40 mg/ml

8ml, 10ml

€119.00

CURE FIP™ Dual Antiviral Oral Capsules

See weight bands below

Capsule

€179.00

Higher concentrations such as the 40mg/ml option mean a smaller injection volume per dose, which can be more comfortable for larger cats. Your veterinarian will help you match the concentration to your cat's weight and form of FIP.

Injectable GS-441524 monotherapy

Injectable GS-441524 monotherapy is the route tied to the strongest single-arm evidence. Evidence shows GS-441524 monotherapy reached a 92% success rate in the UC Davis field study (Pedersen, 2019). All three CureFIP injectables follow the same form-based dosing and the same 84-day schedule.

Oral dual antiviral capsules

The CURE FIP™ Dual Antiviral Oral Capsules combine GS-441524 with EIDD-1931 and are dosed by weight, one capsule per day, every day, for a recommended 12 weeks. Evidence shows the dual antiviral approach reported 78.3% remission (Li and Cheah, 2025). The catalog dosing by weight band is below.

Weight band

Per capsule

Under 2.5 kg

GS-441524 25 mg + EIDD-1931 5 mg

2.5 to 5 kg

GS-441524 35 mg + EIDD-1931 8 mg

Over 5 kg

GS-441524 50 mg + EIDD-1931 12 mg

The oral dual route is positioned for wet and dry FIP. Some regions note it is not recommended once ocular or neurological signs are present, or if the cat cannot eat or defecate. EIDD-1931 is teratogenic, so it must not be used in pregnant or lactating queens. Discuss suitability with your veterinarian before choosing the oral route.

How much does FIP treatment cost in the UK?

FIP treatment cost depends on the product, your cat's weight, and the full 84-day course, because daily dosing continues for 12 weeks. CureFIP injectables start at €79.00 for the 20mg/ml option, €89.00 for the 30mg/ml option, and €119.00 for the 40mg/ml option, while the CURE FIP™ Dual Antiviral Oral Capsules are listed at €179.00. We list prices in EUR exactly as shown and do not convert currency. Your total course cost depends on how many vials or capsules your cat needs across the 84 days, which your veterinarian can estimate from your cat's weight.

We are transparent about cost because FIP treatment is a daily commitment over 12 weeks. Budgeting for the full protocol from the start gives your cat the best chance at completing the course without interruption.

What does the FIP treatment journey look like?

The FIP treatment journey is an 84-day daily protocol followed by a monitoring period to confirm remission. Here is the typical sequence:

1. Get a veterinary diagnosis confirming FIP and its form (wet, dry, ocular, or neurological).

2. Agree the product, dose, and route with your veterinarian based on your cat's weight and form.

3. Begin daily GS-441524 dosing and keep to the same time each day.

4. Track appetite, weight, energy, and any side effects, and report changes to your veterinarian.

5. Complete recheck bloodwork during treatment so your veterinarian can adjust if needed.

6. Finish the full 84 days even if your cat looks well early, then enter the observation period.

7. Confirm remission with your veterinarian before stopping monitoring.

Consistency is the single most important factor. Missed or delayed doses can undermine the protocol, so plan the daily routine around your cat from day one.

Should I see a vet, or treat at home?

You should always involve your veterinarian, because diagnosis, dosing, and monitoring all require clinical judgement. Veterinary supervision is essential at every stage of FIP treatment, from confirming the form of FIP to adjusting the dose and verifying remission. CureFIP supplies GS-441524 based products, but the treatment plan belongs with your veterinarian, who knows your cat's full history and current bloodwork.

FAQ

What is the success rate of GS-441524 for FIP?

Evidence shows GS-441524 monotherapy reached a 92% success rate in the UC Davis field study (Pedersen, 2019). The dual antiviral approach combining GS-441524 with EIDD-1931 reported 78.3% remission (Li and Cheah, 2025). The figure that applies depends on which protocol your veterinarian recommends.

How long does FIP treatment take?

A standard course of GS-441524 runs 84 days, given as one dose per day, every day, under veterinary supervision. The CURE FIP™ Dual Antiviral Oral Capsules follow a recommended 12-week course. Completing the full duration is essential even if your cat appears well sooner.

Can oral capsules treat all forms of FIP?

The CURE FIP™ Dual Antiviral Oral Capsules are positioned for wet and dry FIP. Some regions note they are not recommended once ocular or neurological signs are present, or if the cat cannot eat or defecate. Your veterinarian will advise whether the oral or injectable route suits your cat.

How is the daily dose calculated?

The daily dose is calculated from your cat's weight, the form of FIP, and the product concentration. For CureFIP injectables the catalog doses are 6 mg/kg for wet, 8 mg/kg for dry, and 10 mg/kg for ocular and neurological FIP. Your veterinarian confirms the exact volume for your cat.

Is FIP treatment safe for pregnant cats?

The oral dual antiviral and EIDD-1931 products must not be used in pregnant or lactating queens, because EIDD-1931 is teratogenic. Always tell your veterinarian if your cat is pregnant or nursing so a suitable plan can be made. Veterinary guidance is essential before starting any FIP treatment.