Expert Guide: How to Treat FIP Effectively
A practical reference for FIP cat owners using FipDr™ GS-441524. If your question isn't answered here, contact our team — every order includes free veterinary consultation.
How long is the treatment?
The standard protocol is 84 days (12 weeks). Most cats complete treatment within this timeframe.
Some cases may require an extended course depending on:
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The severity of infection
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FIP type (wet, dry, ocular, neurological)
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How quickly your cat responds
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Overall health factors such as age, breed, and pre-existing conditions
Your veterinarian can help determine whether an extension is needed based on bloodwork and clinical signs at the end of the 84-day course.
Do not shorten the treatment, even if your cat appears fully recovered before day 84. Early termination is the leading cause of relapse.
Can GS-441524 be used alongside other medications?
Yes. GS-441524 is an antiviral and does not interfere with most medications commonly used during FIP treatment, including:
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Antibiotics
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Anti-inflammatories
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Appetite stimulants
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Liver support supplements
Two exceptions to note:
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Lysine (L-lysine) is not recommended during GS-441524 treatment — there is no evidence it provides antiviral benefit against FIP, and some clinicians believe it may interfere with treatment efficacy.
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Interferon has shown no meaningful effect against the FIP virus in clinical settings and is not a substitute for antiviral therapy.
What should I feed my cat during FIP treatment?
Prioritize high-protein, easily digestible food — freshly cooked fish, chicken, or other lean meats work well. Caloric intake matters: your cat needs to regain weight, so feed generously and frequently.
If your cat develops diarrhoea, switch to dry food temporarily until stools normalize, then gradually reintroduce wet or fresh food. Persistent diarrhoea beyond 3–4 days warrants a veterinary consultation, as it may indicate a secondary issue unrelated to FIP.
How is the dose calculated for FIP cats?
Dosage is determined by FIP type and your cat's current body weight. Weigh your cat weekly and recalculate — as your cat recovers and gains weight, the dose must increase accordingly.
FIP Type Starting Dose
Wet (effusive) 6 mg/kg
Dry (non-effusive) 8 mg/kg
Ocular 10 mg/kg
Neurological 10 mg/kg
If no clinical improvement is observed by day 5–7, increase the dose by +2 mg/kg. Do not reduce the dose during treatment, even if symptoms appear to resolve — premature dose reduction increases the risk of relapse.
What happens after the 84 days FIP Treatment?
After completing the 84-day course, monitor your cat closely for an additional 84 days (the observation period). If symptoms recur during this window, restart treatment at the previous dose +2 mg/kg.
A cat that remains symptom-free through the full observation period is generally considered to be in sustained remission.
Is GS-441524 safe?
GS-441524 has been used in thousands of FIP cases worldwide since the 2019 Pedersen study at UC Davis. Reported side effects are typically mild and transient: injection-site reactions, occasional inappetence, or short-term elevated liver enzymes.
Each FipDr™ batch is third-party HPLC-purity tested (≥99%) and endotoxin-tested for injectable safety. Certificates of Analysis are available on request.
What if I miss a dose?
Administer the missed dose as soon as you remember. If it's close to the next scheduled dose, do not double up — return to the regular schedule. Consistent daily dosing is critical; if you've missed more than one consecutive day, contact our support team for guidance.
How does shipping work?
We ship from regional fulfillment centers to minimize transit time and avoid customs delays.
RegionShips FromEstimated Delivery
Europe & United KingdomGermany1–2 business days
All orders ship at ambient temperature. GS-441524 in solution is chemically stable under standard shipping conditions. No cold chain is required. Upon delivery, store at room temperature (15–25°C / 59–77°F). Do not refrigerate or freeze.
Each vial is individually packaged in a recyclable paper box, with shipments packed to prevent breakage in transit.
Do I get veterinary support?
Yes. Every order includes free consultation with our trained support team and access to a licensed veterinarian for protocol confirmation, dosing review, and adverse-event handling. Support continues throughout the full 84-day treatment and the 84-day observation period.
Clinical references
Pedersen, N.C. et al. (2019). Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis. Journal of Feline Medicine and Surgery. View published study →
This content is informational and does not replace veterinary advice. All treatment decisions belong to your consulting/treating veterinarian.