Drug profile

The FDA adverse-event record for Trimethoprim-Sulfamethoxazole

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

13
adverse-event reports
7.7%
death-coded share
Dog
most-reported species
4
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.
13
Total Reports
1
Deaths Reported
7.7%
Death Rate

Active Ingredients

Trimethoprim-Sulfamethoxazole

Administration Routes

UnknownOral

Species Affected

Dog 12
Ferret 1

Most Affected Breeds

Retriever - Golden 4
Retriever - Labrador 1
Spitz - Dutch (Keeshond) 1
Schnauzer - Miniature 1
Cattle Dog - Australian (blue heeler, red heeler, Queensland cattledog) 1
Siberian Husky 1
Pit Bull 1
Crossbred Canine/dog 1
Mastiff 1
Unknown 1

Most Reported Reactions

Lethargy (see also Central nervous system depression in 'Neurological') 4
Emesis 4
Frequent urination 4
Cystitis 4
Lack of efficacy (endoparasite) - tapeworm 4
Urinary tract infection 3
Decreased appetite 2
Blood in urine 2
Diarrhoea 2
Tarry or black stool (see also haemorrhagic diarrhoea) 2
Other abnormal test result NOS 2
Lack of efficacy - NOS 2

Outcome Breakdown

Outcome Unknown
6 (46.2%)
Recovered/Normal
5 (38.5%)
Euthanized
1 (7.7%)
Ongoing
1 (7.7%)

Trimethoprim-Sulfamethoxazole Adverse Event Insights

13 reports name Trimethoprim-Sulfamethoxazole; 1 recorded a death outcome (7.7% of reported events, not a population-level mortality rate). Active ingredient: Trimethoprim-Sulfamethoxazole. Administration routes: Unknown, Oral.

By species: Dog (12 reports), Ferret (1 reports). By breed: Retriever - Golden (4), Retriever - Labrador (1), Spitz - Dutch (Keeshond) (1).

Leading clinical signs: Lethargy (see also Central nervous system depression in 'Neurological') (4), Emesis (4), Frequent urination (4), Cystitis (4). Outcome, 13 coded reports: Outcome Unknown leads at 46.2%.

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.