Drug profile

The FDA adverse-event record for Nexgard

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

161
adverse-event reports
4.3%
death-coded share
Dog
most-reported species
18
Lack of efficacy (bacteria) - Borrelia - 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.
161
Total Reports
7
Deaths Reported
4.3%
Death Rate

Active Ingredients

Nexgard

Administration Routes

OralUnknownTopical

Species Affected

Dog 157
Cat 4

Most Affected Breeds

Retriever - Labrador 25
Retriever - Golden 18
Shepherd Dog - German 12
Terrier - Bull - American Pit 11
Crossbred Canine/dog 7
Shepherd Dog - Australian 6
Terrier - Boston 4
Boxer (German Boxer) 4
Domestic Shorthair 4
Mixed (Dog) 4

Most Reported Reactions

Lack of efficacy (bacteria) - Borrelia 18
Diarrhoea 13
Seizure NOS 13
Vomiting 12
Polyuria 9
Not eating 9
Lack of efficacy (endoparasite) - heartworm 9
Elevated alanine aminotransferase (ALT) 7
Weakness 7
Weight loss 6
Polydipsia 6
Lack of efficacy - NOS 6

Outcome Breakdown

Ongoing
108 (67.1%)
Recovered/Normal
24 (14.9%)
Outcome Unknown
22 (13.7%)
Euthanized
5 (3.1%)
Died
2 (1.2%)

Nexgard Adverse Event Insights

161 reports name Nexgard; 7 recorded a death outcome (4.3% of reported events, not a population-level mortality rate). Active ingredient: Nexgard. Administration routes: Oral, Unknown, Topical.

By species: Dog (157 reports), Cat (4 reports). By breed: Retriever - Labrador (25), Retriever - Golden (18), Shepherd Dog - German (12).

Leading clinical signs: Lack of efficacy (bacteria) - Borrelia (18), Diarrhoea (13), Seizure NOS (13), Vomiting (12). Outcome, 161 coded reports: Ongoing leads at 67.1%.

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.