Drug profile

The FDA adverse-event record for Trimethoprim Sulfa

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

32
adverse-event reports
28.1%
death-coded share
Dog
most-reported species
10
Lethargy (see also Central nervous system depression in 'Neurological') - 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.
32
Total Reports
9
Deaths Reported
28.1%
Death Rate

Active Ingredients

Trimethoprim Sulfa

Administration Routes

UnknownOral

Species Affected

Dog 25
Horse 5
Rabbit 1
Cat 1

Most Affected Breeds

Retriever - Labrador 5
Shepherd Dog - German 3
Deutsche Dogge, Great Dane 3
Terrier - Bull - American Pit 3
Thoroughbred 2
Retriever - Golden 2
Quarter Horse 2
Pug 2
Weimaraner 1
Rabbit (other) 1

Most Reported Reactions

Lethargy (see also Central nervous system depression in 'Neurological') 10
Fever 8
Vomiting 8
Death 6
Anaemia NOS 6
Weight loss 5
Anorexia 4
Other abnormal test result NOS 4
Elevated serum alkaline phosphatase (SAP) 4
Elevated blood urea nitrogen (BUN) 4
Death by euthanasia 3
Decreased appetite 3

Outcome Breakdown

Ongoing
20 (62.5%)
Died
6 (18.8%)
Euthanized
3 (9.4%)
Recovered/Normal
3 (9.4%)

Trimethoprim Sulfa Adverse Event Insights

32 reports name Trimethoprim Sulfa; 9 recorded a death outcome (28.1% of reported events, not a population-level mortality rate). Active ingredient: Trimethoprim Sulfa. Administration routes: Unknown, Oral.

By species: Dog (25 reports), Horse (5 reports), Rabbit (1 reports). By breed: Retriever - Labrador (5), Shepherd Dog - German (3), Deutsche Dogge, Great Dane (3).

Leading clinical signs: Lethargy (see also Central nervous system depression in 'Neurological') (10), Fever (8), Vomiting (8), Death (6). Outcome, 32 coded reports: Ongoing leads at 62.5%.

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.