Drug profile

The FDA adverse-event record for Milbemycin Oxime

9,719 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Milbemycin Oxime. See the species affected, top reactions, and outcomes below.

9,719
adverse-event reports
3.9%
death-coded share
Dog
most-reported species
2,087
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.
9,719
Total Reports
378
Deaths Reported
3.9%
Death Rate

Active Ingredients

Milbemycin Oxime

Administration Routes

OralUnknownAuricular (Otic)TopicalOtherIntraocularIntrauterineRespiratory (Inhalation)CutaneousUrethral

Species Affected

Dog 8,952
Unknown 542
Cat 199
Human 21
Other Canids 1
Primate 1
Rabbit 1
Cockatiel 1
Ferret 1

Most Affected Breeds

Retriever - Labrador 1,524
Unknown 574
Crossbred Canine/dog 561
Shepherd Dog - German 464
Retriever - Golden 418
Dog (unknown) 335
Beagle 294
Shepherd Dog - Australian 227
Chihuahua 216
Pit Bull 210

Most Reported Reactions

INEFFECTIVE, HEARTWORM LARVAE 2,087
Vomiting 1,238
Lack of efficacy (endoparasite) - heartworm 1,181
Lethargy (see also Central nervous system depression in 'Neurological') 653
Diarrhoea 634
Lack of efficacy - NOS 515
Emesis 485
Lack of efficacy (endoparasite) - hookworm 484
Other abnormal test result NOS 329
INEFFECTIVE, ASCARIDS NOS 324
Seizure NOS 321
INEFFECTIVE, HOOKS 273

Outcome Breakdown

Outcome Unknown
3,187 (34.8%)
Ongoing
3,099 (33.8%)
Recovered/Normal
2,388 (26.1%)
Died
232 (2.5%)
Euthanized
146 (1.6%)
Recovered with Sequela
113 (1.2%)

Milbemycin Oxime Adverse Event Insights

9,719 reports name Milbemycin Oxime; 378 recorded a death outcome (3.9% of reported events, not a population-level mortality rate). Active ingredient: Milbemycin Oxime. Administration routes: Oral, Unknown, Auricular (Otic), Topical.

By species: Dog (8,952 reports), Unknown (542 reports), Cat (199 reports). By breed: Retriever - Labrador (1,524), Unknown (574), Crossbred Canine/dog (561).

Leading clinical signs: INEFFECTIVE, HEARTWORM LARVAE (2,087), Vomiting (1,238), Lack of efficacy (endoparasite) - heartworm (1,181), Lethargy (see also Central nervous system depression in 'Neurological') (653). Outcome, 9,165 coded reports: Outcome Unknown leads at 34.8%.

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.