ExoticRx · exoticrx.com/drugs/famciclovir
US brand names:Famvir
Famciclovir is dosed at 20–40 mg/kg PO q8-12h in rabbits, per Carpenter's Exotic Animal Formulary, 6th Ed. Verify against current literature before clinical use.
Prodrug of penciclovir. Inhibits viral DNA polymerase in herpesvirus. Used for feline herpesvirus-1 (FHV-1) infections.
First-line antiviral for FHV-1 in cats. Higher doses needed in cats (90mg/kg) due to lower conversion to penciclovir. Well tolerated. May cause GI upset.
Species references:All Cat (Domestic) drugsAll Rabbit (Domestic) drugs
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.
| Species | Route | Dose | Frequency | Evidence | Source |
|---|---|---|---|---|---|
| Cat (Domestic) | PO | 90 mg/kg | q8h | Strong | Sebbag L, Thomasy SM, Woodward AP, Knych HK, Maggs DJ. Pharmacokinetic modeling of penciclovir and BRL42359 in the plasma and tears of healthy cats to optimize dosage recommendations for oral administration of famciclovir. Am J Vet Res. 2016;77(8):833-845. doi:10.2460/ajvr.77.8.833 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.526 (2026-08-01). |
| Cat (Domestic) | PO | 40–90 mg/kg | q8-12h | Strong | Sebbag L, Thomasy SM, Woodward AP, Knych HK, Maggs DJ. Pharmacokinetic modeling of penciclovir and BRL42359 in the plasma and tears of healthy cats to optimize dosage recommendations for oral administration of famciclovir. Am J Vet Res. 2016;77(8):833-845. doi:10.2460/ajvr.77.8.833 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.526 (2026-08-01). |
Upgrade to Pro or Student to unlock the full dose ranges and frequency for every species. The drug's mechanism, warnings, indications, and cited sources are free to read.
View PlansSource citations and evidence levels available on the live page. Reference only — verify against current literature before clinical use.