Trimethoprim-Sulfamethoxazole
13 adverse event reports submitted to the FDA
Active Ingredients
Administration Routes
Species Affected
Most Affected Breeds
Most Reported Reactions
Outcome Breakdown
Data Summary
| Metric | Value |
|---|---|
| Total adverse event reports | 13 |
| Reports involving death | 1 |
| Case-fatality rate (reported events) | 770.0% |
| Distinct species in reports | 2 |
| Distinct breeds in reports | 10 |
| Distinct reactions reported | 20 |
| Active ingredients on file | 1 |
Source: FDA Center for Veterinary Medicine — Adverse Event Reporting (CVM AER). Counts reflect voluntary reports only.
Trimethoprim-Sulfamethoxazole Adverse Event Insights
The FDA Center for Veterinary Medicine database currently holds 13 adverse event reports referencing Trimethoprim-Sulfamethoxazole, including 1 reports in which the animal died — a 770.0% case-fatality figure among reported events only, not a population-level mortality rate. Active ingredient on file: Trimethoprim-Sulfamethoxazole. Reported administration routes include Unknown, Oral. These numbers reflect voluntary submissions from pet owners, veterinarians, and manufacturers and therefore under-represent mild events and over-represent severe ones — a pattern the FDA has documented repeatedly for pharmacovigilance datasets.
The species most frequently named in Trimethoprim-Sulfamethoxazole reports are Dog (12 reports), Ferret (1 reports), with Dog accounting for the largest share. Within those species, Retriever - Golden (4), Retriever - Labrador (1), Spitz - Dutch (Keeshond) (1) appear most often — though breed popularity and ownership density shape these counts as much as any drug-specific sensitivity. This distribution matters because the same active ingredient can behave very differently across body sizes, ages, and species physiology.
The most commonly reported clinical signs associated with Trimethoprim-Sulfamethoxazole are Lethargy (see also Central nervous system depression in 'Neurological') (4), Emesis (4), Frequent urination (4), Cystitis (4). Of the 13 reports with a coded outcome, Outcome Unknown is the leading category at 46.2%. Because FDA adverse event data describes correlation rather than causation, these figures are best used to frame informed questions with a veterinarian and to compare reporting patterns across related products — not as a standalone safety verdict on Trimethoprim-Sulfamethoxazole.
Source: FDA Center for Veterinary Medicine — Adverse Event Reports FDA Center for Veterinary Medicine — Adverse Event Reports Data reflects voluntary submissions and may not represent actual incidence rates
Read our methodology — how this data is sourced, computed, and verified.