Drug profile

The FDA adverse-event record for Heartgard Plus

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

138
adverse-event reports
2.2%
death-coded share
Dog
most-reported species
83
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.
138
Total Reports
3
Deaths Reported
2.2%
Death Rate

Active Ingredients

Heartgard Plus

Administration Routes

OralUnknown

Species Affected

Dog 138

Most Affected Breeds

Retriever - Labrador 16
Crossbred Canine/dog 11
Chihuahua 10
Terrier - Bull - American Pit 8
Retriever - Golden 7
Shepherd Dog - German 6
Beagle 5
Terrier (unspecified) 4
Shepherd Dog - Australian 3
Shepherd Dog - Belgian Malinois 3

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 83
Seizure NOS 8
Polyuria 7
Urinary incontinence 6
Lethargy (see also Central nervous system depression in Neurological) 5
Decreased appetite 4
Vomiting 4
Twitching 4
Emesis (multiple) 4
Diarrhoea 4
Urinary tract infection 4
Ataxia 3

Outcome Breakdown

Ongoing
104 (75.4%)
Outcome Unknown
19 (13.8%)
Recovered/Normal
12 (8.7%)
Euthanized
2 (1.4%)
Died
1 (0.7%)

Heartgard Plus Adverse Event Insights

138 reports name Heartgard Plus; 3 recorded a death outcome (2.2% of reported events, not a population-level mortality rate). Active ingredient: Heartgard Plus. Administration routes: Oral, Unknown.

By species: Dog (138 reports). By breed: Retriever - Labrador (16), Crossbred Canine/dog (11), Chihuahua (10).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (83), Seizure NOS (8), Polyuria (7), Urinary incontinence (6). Outcome, 138 coded reports: Ongoing leads at 75.4%.

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.