Drug profile

The FDA adverse-event record for Nexgard

169 FDA reports name Nexgard, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#586 of 2,679
by report volume (all drugs)
169
adverse-event reports
4.1%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Nexgard ranks #582 of 2679 by total reports (169) and #836 of 1130 by death-coded share (4.1%). National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#582
This drug, reports of 2679
#836
This drug, death share of 1130

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Nexgard has 169 reports now versus 168 in that prior snapshot: 1 more (0.6%).

Report change
+1
Death-coded reports
+0
Death-coded share
−0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Nexgard changes

Signature read: 169 reports place Nexgard in the upper third of FDA AER volume (#586 of 2,679).

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
169
Total Reports
7
Deaths Reported
4.1%
Death-coded share of reports

Active Ingredients

Nexgard

Administration Routes

OralUnknownTopical

Species Affected

Dog 165
Cat 4

Most Affected Breeds

Retriever - Labrador 26
Retriever - Golden 19
Shepherd Dog - German 13
Terrier - Bull - American Pit 12
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 20
Seizure NOS 14
Diarrhoea 13
Vomiting 12
Not eating 10
Lack of efficacy (endoparasite) - heartworm 10
Polyuria 9
Lack of efficacy - NOS 8
Elevated alanine aminotransferase (ALT) 7
Weakness 7
Intentional misuse 7
Weight loss 6

Outcome Breakdown

Ongoing
113 (66.9%)
Recovered/Normal
26 (15.4%)
Outcome Unknown
23 (13.6%)
Euthanized
5 (3.0%)
Died
2 (1.2%)

Nexgard: low death-coded share in the FDA AER row

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.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Nexgard, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Nexgard (#586 of 2,679 by report volume); death-coded 4.1%. PlainBreed drug row · report volume stamp 169 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →