Drug profile

The FDA adverse-event record for Trifexis

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

84
adverse-event reports
6.0%
death-coded share
Dog
most-reported species
55
Lack of efficacy (endoparasite) - heartworm - 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.
84
Total Reports
5
Deaths Reported
6.0%
Death Rate

Active Ingredients

Trifexis

Administration Routes

OralUnknownTopical

Species Affected

Dog 84

Most Affected Breeds

Retriever - Labrador 13
Shepherd Dog - German 8
Crossbred Canine/dog 4
Terrier (unspecified) 4
Shepherd Dog - Australian 4
Dachshund (unspecified) 3
Terrier - Bull - American Pit 3
Chihuahua 3
Bulldog - French 2
Shih Tzu 2

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 55
Seizure NOS 6
Diarrhoea 4
Vomiting 3
Drug dose administration interval too long 3
Ataxia 3
Lethargy (see also Central nervous system depression in 'Neurological') 3
Medication error NOS 3
Aggression 2
Bruising 2
Growling 2
Lack of efficacy (ectoparasite) - flea 2

Outcome Breakdown

Ongoing
67 (79.8%)
Recovered/Normal
5 (6.0%)
Outcome Unknown
5 (6.0%)
Died
3 (3.6%)
Recovered with Sequela
2 (2.4%)
Euthanized
2 (2.4%)

Trifexis Adverse Event Insights

84 reports name Trifexis; 5 recorded a death outcome (6.0% of reported events, not a population-level mortality rate). Active ingredient: Trifexis. Administration routes: Oral, Unknown, Topical.

By species: Dog (84 reports). By breed: Retriever - Labrador (13), Shepherd Dog - German (8), Crossbred Canine/dog (4).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (55), Seizure NOS (6), Diarrhoea (4), Vomiting (3). Outcome, 84 coded reports: Ongoing leads at 79.8%.

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.