Cat Feline Infectious Peritonitis Management

Feline infectious peritonitis (FIP) was once uniformly fatal; antiviral treatments now offer genuine cure in most cases, transforming the welfare outlook.

Key Facts

FIP is caused by a mutated form of feline coronavirus, predominantly affecting young cats.
Before 2019, FIP was considered universally fatal with a median survival of weeks after diagnosis.
Antiviral drugs — GS-441524 and molnupiravir — achieve remission in over 85% of cases when treatment is completed.
Treatment courses last 84 days; follow-up monitoring extends for 12 months to confirm sustained remission.
GS-441524 was initially available only in unlicensed form via importation, but licensed products are now available in many markets.

Welfare Considerations

FIP causes severe welfare compromise — fever, weight loss, fluid accumulation, neurological signs, and ocular disease — before treatment became available. The transformation of FIP from a death sentence to a manageable and often curable condition represents one of veterinary medicine's most remarkable recent advances. Cats undergoing treatment typically show dramatic improvement within 1-2 weeks. Treatment completion is essential; premature discontinuation risks relapse. The availability and cost of treatment remain welfare challenges, with significant geographic variability in access. Owner financial support resources and veterinary awareness are critical to ensuring treated cats receive the full course.

What You Can Do

If your cat is diagnosed with FIP, immediately seek a vet experienced with GS-441524 treatment.
Research FIP support groups that can advise on accessing licensed or unlicensed treatment.
Complete the full 84-day treatment course even when your cat appears to have fully recovered.
Support advocacy for affordable, licensed FIP treatments to be available in all markets.