Drug profile

The FDA adverse-event record for Heartgard

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

360
adverse-event reports
5.3%
death-coded share
Dog
most-reported species
167
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.
360
Total Reports
19
Deaths Reported
5.3%
Death Rate

Active Ingredients

Heartgard

Administration Routes

OralUnknownTopicalSubcutaneous

Species Affected

Dog 360

Most Affected Breeds

Retriever - Labrador 50
Crossbred Canine/dog 30
Shepherd Dog - German 30
Terrier - Bull - American Pit 24
Retriever - Golden 18
Boxer (German Boxer) 12
Terrier (unspecified) 11
Chihuahua 9
Beagle 9
Shepherd Dog - Australian 7

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 167
Vomiting 41
Seizure NOS 21
Diarrhoea 18
Weight loss 14
Panting 14
Lethargy (see also Central nervous system depression in 'Neurological') 13
Emesis (multiple) 13
Death by euthanasia 13
Anorexia 12
Lethargy (see also Central nervous system depression in Neurological) 12
Polyuria 10

Outcome Breakdown

Ongoing
262 (72.8%)
Recovered/Normal
45 (12.5%)
Outcome Unknown
33 (9.2%)
Euthanized
13 (3.6%)
Died
6 (1.7%)
Recovered with Sequela
1 (0.3%)

Heartgard Adverse Event Insights

360 reports name Heartgard; 19 recorded a death outcome (5.3% of reported events, not a population-level mortality rate). Active ingredient: Heartgard. Administration routes: Oral, Unknown, Topical, Subcutaneous.

By species: Dog (360 reports). By breed: Retriever - Labrador (50), Crossbred Canine/dog (30), Shepherd Dog - German (30).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (167), Vomiting (41), Seizure NOS (21), Diarrhoea (18). Outcome, 360 coded reports: Ongoing leads at 72.8%.

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.