nexgard — FDA Animal & Veterinary Adverse Event (ADE) Reports
Source: openFDA animalandveterinary/event.json, the FDA Center for Veterinary Medicine (CVM) adverse event report database. Data pulled 2026-08-16. Counts are report-level: one report may list multiple reactions and multiple animals, so figures are not additive and do not imply causation. "nexgard" is a name as filed in the drug active-ingredient field of these reports (may be a generic ingredient or a product/brand name as reported).
Total reports
nexgard: 236
Reports by species (top entries)
- Dog 226
- Cat 10
Top reported reactions (VEDDRA terms, top entries)
- Lack of efficacy (endoparasite) - heartworm 26
- Lack of efficacy (bacteria) - Borrelia 24
- Seizure NOS 19
- Vomiting 17
- Diarrhoea 14
- Lethargy (see also Central nervous system depression in Neurological) 12
- Death by euthanasia 11
- Elevated alanine aminotransferase (ALT) 11
- Lack of efficacy - NOS 11
- Not eating 11
"Lack of efficacy" terms denote product-performance reports, not adverse reactions.
Source JSON: pdf-raw/ade/ade_active_ingredients_2026-08-16_b1.json (openFDA animalandveterinary/event.json, pulled 2026-08-16).