What is Molnupiravir
What is Molnupiravir?
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.
How Molnupiravir Works in Cats
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.
Possible Side Effects of Molnupiravir
- 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.
What to Do if a Dose Is Missed
If the cat misses a dose, give the next dose as soon as possible or, if it is close to the next scheduled dose, return to the regular schedule. Do not give two doses (double dose) to catch up. If owners are not sure what to do, they should call their veterinarian and follow their directions.
Case Studies
Journal of Veterinary Internal MedicineMolnupiravir treatment of 18 cats with feline infectious peritonitis: A case series
doi:10.1111/jvim.16832
FIRST PUBLISHED
08-AUG-2023
AUTHOR
Okihiro Sase
BACKGROUND
Feline infectious peritonitis (FIP) is a viral disease in cats, caused by certain strains of coronavirus and has a high case fatality rate.
OBJECTIVE
This case series reports the outcomes of treatment of cats with FIP using molnupiravir.
ANIMALS
Eighteen cats diagnosed with FIP at the You-Me Animal Clinic, Sakura-shi, Japan between January and August 2022, and whose owners gave informed consent to this experimental treatment.
METHODS
For this prospective observational study, molnupiravir tablets were compounded in-house at the You-Me Animal Clinic. Owners administered 10-20 mg/kg PO twice daily. Standard treatment duration was 84 days.
RESULTS
Among 18 cats, 13 cats had effusive FIP and 5 had noneffusive FIP. Three cats had neurological or ocular signs of FIP before treatment. Four cats, all with effusive FIP, died or were euthanized within 7 days of starting treatment. The remaining 14 cats completed treatment and remained in remission at the time of writing (139-206 days after starting treatment). Elevated serum alanine transaminase (ALT) activity was found in 3 cats, all at Days 7-9, and all recovered without management. Two cats with jaundice were hospitalized, 1 during treatment (Day 37) and 1 with severe anemia at the start of treatment.
CONCLUSIONS AND CLINICAL IMPORTANCE
This case series suggests that molnupiravir might be an effective and safe treatment for domestic cats with FIP at a dose of 10-20 mg/kg twice daily.
DOWNLOAD CASE REPORT
The following downloadable file is in .pdf format and will require the use of a document reader such as Adobe Acrobat.
MDPI JournalsUnlicensed Molnupiravir is an Effective Rescue Treatment Following Failure of Unlicensed GS-441524-like Therapy for Cats with Suspected Feline Infectious Peritonitis
doi.org/10.3390/pathogens11101209
FIRST PUBLISHED
20-OCT-2022
AUTHORS
Meagan Roy, Nicole Jacque, Wendy Novicoff, Emma Li, Rosa Negash and Samantha J. M. Evans
ABSTRACT
Feline infectious peritonitis (FIP) is a complex and historically fatal disease, though recent advances in antiviral therapy have uncovered potential treatments. A newer therapeutic option, unlicensed molnupiravir, is being used as a first-line therapy for suspect FIP and as a rescue therapy to treat cats who have persistent or relapsed clinical signs of FIP after GS-441524 and/or GC376 therapy. Using owner-reported data, treatment protocols for 30 cats were documented. The 26 cats treated with unlicensed molnupiravir as a rescue therapy were treated with an average starting dosage of 12.8 mg/kg and an average ending dosage of 14.7 mg/kg twice daily for a median of 12 weeks (IQR = 10–15). In total, 24 of 26 cats were still living disease-free at the time of writing. One cat was euthanized after completing treatment due to a prolonged seizure, and the other cat underwent retreatment for relapsed clinical signs. Few adverse effects were reported, with the most notable—folded ears (1), broken whiskers (1), and severe leukopenia (1)—seen at dosages above 23 mg/kg twice daily. This study provides a proof of principle for the use of molnupiravir in cats and supports the need for future studies to further evaluate molnupiravir as a potentially safe and effective therapy for FIP.
DOWNLOAD CASE REPORT
The following downloadable file is in .pdf format and will require the use of a document reader such as Adobe Acrobat.