Drug profile

The FDA adverse-event record for Ivermectin/Pyrantel

1,031 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Ivermectin/Pyrantel. See the species affected, top reactions, and outcomes below.

1,031
adverse-event reports
3.6%
death-coded share
Dog
most-reported species
281
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.
1,031
Total Reports
37
Deaths Reported
3.6%
Death Rate

Active Ingredients

Ivermectin/Pyrantel

Administration Routes

OralUnknownTopical

Species Affected

Dog 1,028
Unknown 3

Most Affected Breeds

Retriever - Labrador 169
Crossbred Canine/dog 96
Shepherd Dog - German 62
Retriever - Golden 38
Chihuahua 29
Terrier - Bull - American Pit 29
Boxer (German Boxer) 28
Terrier (unspecified) 28
Shih Tzu 25
Dog (unknown) 24

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 281
INEFFECTIVE, HEARTWORM LARVAE 178
Vomiting 149
Lethargy (see also Central nervous system depression in 'Neurological') 86
Diarrhoea 74
Seizure NOS 59
Lack of efficacy - NOS 38
Anorexia 33
Weight loss 31
Lack of efficacy (heartworm) 31
Emesis 30
Decreased appetite 29

Outcome Breakdown

Outcome Unknown
409 (39.8%)
Ongoing
351 (34.1%)
Recovered/Normal
226 (22.0%)
Euthanized
26 (2.5%)
Died
11 (1.1%)
Recovered with Sequela
5 (0.5%)

Ivermectin/Pyrantel Adverse Event Insights

1,031 reports name Ivermectin/Pyrantel; 37 recorded a death outcome (3.6% of reported events, not a population-level mortality rate). Active ingredient: Ivermectin/Pyrantel. Administration routes: Oral, Unknown, Topical.

By species: Dog (1,028 reports), Unknown (3 reports). By breed: Retriever - Labrador (169), Crossbred Canine/dog (96), Shepherd Dog - German (62).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (281), INEFFECTIVE, HEARTWORM LARVAE (178), Vomiting (149), Lethargy (see also Central nervous system depression in 'Neurological') (86). Outcome, 1,028 coded reports: Outcome Unknown leads at 39.8%.

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.