Drug profile

The FDA adverse-event record for Famciclovir

38 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Famciclovir. See the species affected, top reactions, and outcomes below.

38
adverse-event reports
21.1%
death-coded share
Cat
most-reported species
7
Not eating - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
38
Total Reports
8
Deaths Reported
21.1%
Death Rate

Active Ingredients

Famciclovir

Administration Routes

OralUnknown

Species Affected

Cat 36
Parrot 2

Most Affected Breeds

Domestic Shorthair 21
Domestic Mediumhair 5
Persian 3
Siamese 3
Cat (unknown) 2
Parrot (other) 2
Crossbred Feline/cat 1
Domestic Longhair 1

Most Reported Reactions

Not eating 7
Anaemia NOS 6
Lack of efficacy (bacteria) - NOS 6
Lack of efficacy - NOS 6
Lethargy (see also Central nervous system depression in 'Neurological') 5
Dehydration 5
Wobbliness 5
Death by euthanasia 4
Nasal bleeding 4
Death 4
Vomiting 4
Weakness 4

Outcome Breakdown

Ongoing
12 (31.6%)
Outcome Unknown
12 (31.6%)
Recovered/Normal
6 (15.8%)
Euthanized
4 (10.5%)
Died
4 (10.5%)

Famciclovir Adverse Event Insights

38 reports name Famciclovir; 8 recorded a death outcome (21.1% of reported events, not a population-level mortality rate). Active ingredient: Famciclovir. Administration routes: Oral, Unknown.

By species: Cat (36 reports), Parrot (2 reports). By breed: Domestic Shorthair (21), Domestic Mediumhair (5), Persian (3).

Leading clinical signs: Not eating (7), Anaemia NOS (6), Lack of efficacy (bacteria) - NOS (6), Lack of efficacy - NOS (6). Outcome, 38 coded reports: Ongoing leads at 31.6%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.