Molnupiravir: oral-only FIP treatment
Molnupiravir is the all-oral antiviral for FIP — no injections required. Particularly valuable for cats that tolerate injections poorly and owners unable to administer subcutaneous medication.
How does Molnupiravir work?
Molnupiravir is a prodrug that, once metabolized, introduces errors into the viral RNA during replication. This mechanism — known as "error catastrophe" — leads to the collapse of viral replication. While its mechanism differs from GS-441524, the final result is the same: viral replication stops and the cat's immune system can recover.
The key advantage over GS-441524 is administration route: Molnupiravir is given exclusively as oral capsules or liquid suspension, eliminating the need for daily subcutaneous injections. This is particularly beneficial for cats with fragile skin, owners uncomfortable with needles, or cats in stressful injection situations.
Recommended dosing
| FIP Form | Dose | Route | Duration |
|---|---|---|---|
| Wet/dry FIP (standard) | 15-17 mg/kg/day | Oral only | 84 days |
| Dry FIP without neuro/ocular | 17 mg/kg/day | Oral only | 84 days |
| Neurological or ocular FIP | 20 mg/kg/day | Oral only | 84+ days |
Molnupiravir vs GS-441524
Molnupiravir
- Oral only (no injections)
- Easier administration
- Well tolerated
- Higher dose volume needed
- Less data for neuro forms
GS-441524
- Injectable or oral options
- SC preferred for neuro forms
- Most studied antiviral
- Daily injections required (SC)
- More brands available
FAQ
Questions about Molnupiravir
Clear answers to the most common questions.
Standard dose is 15-20 mg/kg/day for most FIP forms. Neurological or ocular forms typically require the higher end of 20 mg/kg/day. Always under veterinary supervision.
Molnupiravir shows comparable efficacy to GS-441524 in most FIP forms. Some studies suggest slightly lower cure rates for neurological forms, but it offers the clear advantage of being exclusively oral — no injections needed.
Yes. Dual therapy combining both antivirals is used for resistant cases, neurological FIP, or when standard monotherapy fails. This is an emerging protocol with promising results but requires careful veterinary management.
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