Drug profile

The FDA adverse-event record for Penicillin

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

387
adverse-event reports
28.7%
death-coded share
Dog
most-reported species
73
Death - 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.
387
Total Reports
111
Deaths Reported
28.7%
Death Rate

Active Ingredients

Penicillin

Administration Routes

UnknownSubcutaneousParenteralIntramuscularOralOtherTopicalSubconjunctival

Species Affected

Dog 239
Cat 107
Cattle 20
Horse 7
Rabbit 5
Pig 4
Goat 1
Rat 1
Human 1
Other Canids 1

Most Affected Breeds

Domestic Shorthair 68
Retriever - Labrador 29
Domestic Longhair 18
Terrier - Bull - American Pit 10
Chihuahua 9
Pit Bull 9
Shepherd Dog - German 8
Cat (unknown) 8
Shepherd Dog - Australian 8
Boxer (German Boxer) 8

Most Reported Reactions

Death 73
Lethargy (see also Central nervous system depression in 'Neurological') 70
Vomiting 59
Anorexia 57
Other abnormal test result NOS 57
Death by euthanasia 34
Ataxia 33
Diarrhoea 33
Not eating 33
Seizure NOS 31
Weight loss 30
Behavioural disorder NOS 29

Outcome Breakdown

Ongoing
116 (29.0%)
Recovered/Normal
104 (26.0%)
Died
79 (19.8%)
Outcome Unknown
60 (15.0%)
Euthanized
34 (8.5%)
Recovered with Sequela
7 (1.8%)

Penicillin Adverse Event Insights

387 reports name Penicillin; 111 recorded a death outcome (28.7% of reported events, not a population-level mortality rate). Active ingredient: Penicillin. Administration routes: Unknown, Subcutaneous, Parenteral, Intramuscular.

By species: Dog (239 reports), Cat (107 reports), Cattle (20 reports). By breed: Domestic Shorthair (68), Retriever - Labrador (29), Domestic Longhair (18).

Leading clinical signs: Death (73), Lethargy (see also Central nervous system depression in 'Neurological') (70), Vomiting (59), Anorexia (57). Outcome, 400 coded reports: Ongoing leads at 29.0%.

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.