GS-441524 Treatment for FIP: The Complete Guide
GS-441524 is a nucleoside analog antiviral developed by Gilead Sciences. It was first studied for FIP treatment by UC Davis researchers (Pedersen et al., 2019) and has since become the standard of care for FIP worldwide.
How GS-441524 Works
GS-441524 is a prodrug of GS-443902, an adenosine nucleotide analog. Once inside infected cells, it inhibits RNA-dependent RNA polymerase — the enzyme FCoV uses to replicate. By blocking viral replication, the drug allows the immune system to eliminate the infection.
Treatment Protocols by FIP Type
| FIP Type | Recommended Dose | Duration |
|---|---|---|
| Wet (Effusive) | 4–6 mg/kg/day SC | 84 days minimum |
| Dry (Non-Effusive) | 6–8 mg/kg/day SC | 84 days minimum |
| Ocular | 8–10 mg/kg/day SC | 84 days minimum |
| Neurological | 10–12 mg/kg/day SC | 84 days minimum |
SC = subcutaneous injection. Doses may be adjusted based on response and body weight.
Important: Always work with a veterinarian familiar with FIP treatment to determine the correct dose for your cat. Starting too low is a common cause of treatment failure.
The 84-Day Protocol
The standard treatment protocol is: 1. 84 days of daily antiviral injections at the appropriate dose 2. 12-week observation period after completing injections — no medication 3. At 12 weeks post-treatment: recheck bloodwork and clinical signs 4. If no relapse: cat is considered in remission (cured)
Approximately 85% of cats completing the protocol achieve sustained remission.
Monitoring During Treatment
You should expect to see improvement within: - 1–3 days: Increased appetite, more energy - 1–2 weeks: Reduction in fever, fluid drainage (wet FIP) - 4 weeks: Bloodwork beginning to normalize
Regular monitoring includes: - Complete blood count (CBC) — every 2–4 weeks - Albumin/Globulin (A:G) ratio - Body weight - General clinical signs
Relapse and Re-Treatment
Relapse occurs in approximately 10–15% of cases. Common causes: - Underdosing (most common) - Stopping treatment too early - Neurological or ocular involvement requiring higher doses
Cats that relapse can typically be re-treated successfully with a dose increase.
Where to Buy GS-441524
GS-441524 is not yet FDA-approved for veterinary use in the US. It is available through:
- Licensed compounding pharmacies — requires veterinary prescription
- Established online suppliers — several suppliers with documented cure records; ask in the SOCK FIP or FIP Warriors Facebook groups for current recommendations
- FIP Warriors 5.0 program — provides sourcing guidance and support
Always verify the source. Community groups like FIP Warriors maintain updated lists of trusted suppliers and warn against counterfeit products.
Cost of Treatment
Full 84-day treatment costs vary: - Compounding pharmacy (US): $3,000–$6,000+ total - International suppliers: $800–$2,500 total
High cost has driven many owners to international sourcing. The FIP Warriors community maintains sourcing guides.