Drug profile

The FDA adverse-event record for Milbemycin Oxime & Lufenuron

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

538
adverse-event reports
4.1%
death-coded share
Dog
most-reported species
109
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.
538
Total Reports
22
Deaths Reported
4.1%
Death Rate

Active Ingredients

Milbemycin Oxime & Lufenuron

Administration Routes

OralUnknown

Species Affected

Dog 537
Cat 1

Most Affected Breeds

Retriever - Labrador 91
Retriever - Golden 33
Shepherd Dog - German 22
Beagle 20
Terrier - Bull - American Pit 19
Chihuahua 18
Shih Tzu 17
Shepherd Dog - Australian 12
Terrier - Yorkshire 12
Maltese 12

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 109
Vomiting 95
Lethargy (see also Central nervous system depression in 'Neurological') 81
Seizure NOS 56
Diarrhoea 41
Lack of efficacy - NOS 36
Tremor 34
INEFFECTIVE, HEARTWORM LARVAE 30
Anorexia 29
Other abnormal test result NOS 23
Elevated alanine aminotransferase (ALT) 23
Ataxia 19

Outcome Breakdown

Ongoing
353 (65.6%)
Recovered/Normal
100 (18.6%)
Outcome Unknown
63 (11.7%)
Died
12 (2.2%)
Euthanized
10 (1.9%)

Milbemycin Oxime & Lufenuron Adverse Event Insights

538 reports name Milbemycin Oxime & Lufenuron; 22 recorded a death outcome (4.1% of reported events, not a population-level mortality rate). Active ingredient: Milbemycin Oxime & Lufenuron. Administration routes: Oral, Unknown.

By species: Dog (537 reports), Cat (1 reports). By breed: Retriever - Labrador (91), Retriever - Golden (33), Shepherd Dog - German (22).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (109), Vomiting (95), Lethargy (see also Central nervous system depression in 'Neurological') (81), Seizure NOS (56). Outcome, 538 coded reports: Ongoing leads at 65.6%.

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.