Molnupiravir is an antiviral medication designed primarily to treat mild to moderate COVID-19 in humans. However, clinical studies have demonstrated that it can also serve as an off-label rescue therapy for cats suffering from Feline Infectious Peritonitis (FIP) both as a first line of treatment and as a secondary line of treatment when GS-441524 has been shown to be ineffective.

Molnupiravir interferes with the FIP virus enzymes and biological processes. Veterinarians may also recommend adding an immunosuppressive treatment, like prednisolone, to reduce inflammation. Studies state that molnupiravir is a safe and effective option for FIP, typically requiring a 12-week treatment period to eliminate the virus. Dosing may change based on the cat’s weight and response to treatment, particularly as the cat successfully regains weight after starting the medication.

• Folded ears
• Broken whiskers
• Diarrhea
• Nausea
• Vomiting
• Hives, itching, skin rash, redness of the skin
• In dosages above 23 mg/kg twice daily, severe leukopenia (lower-than-normal number of white blood cells) is possible.