Drug profile

The FDA adverse-event record for Ivermectin & Pyrantel

575 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Ivermectin & Pyrantel. See the species affected, top reactions, and outcomes below.

575
adverse-event reports
2.8%
death-coded share
Dog
most-reported species
209
Lack of efficacy (endoparasite) - heartworm - top reaction
Verify with FDA CVM →
Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
575
Total Reports
16
Deaths Reported
2.8%
Death Rate

Active Ingredients

Ivermectin & Pyrantel

Administration Routes

OralUnknownOphthalmic

Species Affected

Dog 574
Cat 1

Most Affected Breeds

Retriever - Labrador 88
Shepherd Dog - German 35
Chihuahua 29
Retriever - Golden 26
Crossbred Canine/dog 18
Terrier - Bull - American Pit 17
Beagle 15
Dog (unknown) 15
Terrier (unspecified) 14
Dachshund (unspecified) 13

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 209
Vomiting 74
Seizure NOS 53
Lethargy (see also Central nervous system depression in 'Neurological') 45
Lack of efficacy - NOS 38
Diarrhoea 28
INEFFECTIVE, HEARTWORM LARVAE 27
Ataxia 24
INEFFECTIVE, HEARTWORM ADULTS 24
Anorexia 22
Elevated alanine aminotransferase (ALT) 19
Tremor 18

Outcome Breakdown

Ongoing
402 (69.8%)
Outcome Unknown
87 (15.1%)
Recovered/Normal
71 (12.3%)
Euthanized
9 (1.6%)
Died
7 (1.2%)

Ivermectin & Pyrantel Adverse Event Insights

575 reports name Ivermectin & Pyrantel; 16 recorded a death outcome (2.8% of reported events, not a population-level mortality rate). Active ingredient: Ivermectin & Pyrantel. Administration routes: Oral, Unknown, Ophthalmic.

By species: Dog (574 reports), Cat (1 reports). By breed: Retriever - Labrador (88), Shepherd Dog - German (35), Chihuahua (29).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (209), Vomiting (74), Seizure NOS (53), Lethargy (see also Central nervous system depression in 'Neurological') (45). Outcome, 576 coded reports: Ongoing leads at 69.8%.

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.