Drug profile

The FDA adverse-event record for Milbemycin

6,381 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Milbemycin. See the species affected, top reactions, and outcomes below.

6,381
adverse-event reports
1.7%
death-coded share
Dog
most-reported species
2,776
INEFFECTIVE, HEARTWORM LARVAE - 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.
6,381
Total Reports
109
Deaths Reported
1.7%
Death Rate

Active Ingredients

Milbemycin

Administration Routes

OralUnknownAuricular (Otic)Topical

Species Affected

Dog 6,043
Unknown 290
Cat 33
Human 14
Other 1

Most Affected Breeds

Crossbred Canine/dog 1,422
Retriever - Labrador 1,047
Shepherd Dog - German 306
Unknown 305
Retriever - Golden 250
Beagle 155
Boxer (German Boxer) 142
Dog (unknown) 139
Dachshund (unspecified) 130
Chihuahua 98

Most Reported Reactions

INEFFECTIVE, HEARTWORM LARVAE 2,776
Vomiting 809
INEFFECTIVE, ASCARIDS NOS 749
Lack of efficacy (endoparasite) - hookworm 638
Lack of efficacy (endoparasite) - whipworm 566
Diarrhoea 561
Depression 396
Anorexia 230
Underfilling, Package 176
Convulsion 125
Ataxia 83
Pruritus 70

Outcome Breakdown

Died
104 (56.2%)
Ongoing
48 (25.9%)
Recovered/Normal
13 (7.0%)
Outcome Unknown
11 (5.9%)
Euthanized
5 (2.7%)
Recovered with Sequela
4 (2.2%)

Milbemycin Adverse Event Insights

6,381 reports name Milbemycin; 109 recorded a death outcome (1.7% of reported events, not a population-level mortality rate). Active ingredient: Milbemycin. Administration routes: Oral, Unknown, Auricular (Otic), Topical.

By species: Dog (6,043 reports), Unknown (290 reports), Cat (33 reports). By breed: Crossbred Canine/dog (1,422), Retriever - Labrador (1,047), Shepherd Dog - German (306).

Leading clinical signs: INEFFECTIVE, HEARTWORM LARVAE (2,776), Vomiting (809), INEFFECTIVE, ASCARIDS NOS (749), Lack of efficacy (endoparasite) - hookworm (638). Outcome, 185 coded reports: Died leads at 56.2%.

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.