Drug profile

The FDA adverse-event record for Fipronil + (S)-Methoprene

367 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Fipronil + (S)-Methoprene. See the species affected, top reactions, and outcomes below.

367
adverse-event reports
1.6%
death-coded share
Dog
most-reported species
94
Emesis - 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.
367
Total Reports
6
Deaths Reported
1.6%
Death Rate

Active Ingredients

Fipronil + (S)-Methoprene

Administration Routes

TopicalUnknownOralCutaneousIntraocular

Species Affected

Dog 305
Cat 62

Most Affected Breeds

Retriever - Labrador 41
Domestic Shorthair 24
Dog (unknown) 17
Crossbred Canine/dog 15
Cat (unknown) 15
Shepherd Dog - German 13
Domestic Longhair 11
Shih Tzu 9
Shepherd Dog - Australian 9
Dachshund (unspecified) 8

Most Reported Reactions

Emesis 94
Lack of efficacy (ectoparasite) - flea 67
Vomiting 46
Lethargy (see also Central nervous system depression in 'Neurological') 42
Lack of efficacy - NOS 40
Diarrhoea 18
Behavioural disorder NOS 16
Other abnormal test result NOS 16
Lack of efficacy (flea) 14
Lack of efficacy (endoparasite) - heartworm 14
Panting 12
Seizure NOS 11

Outcome Breakdown

Outcome Unknown
158 (43.1%)
Recovered/Normal
147 (40.1%)
Ongoing
40 (10.9%)
Recovered with Sequela
16 (4.4%)
Died
5 (1.4%)
Euthanized
1 (0.3%)

Fipronil + (S)-Methoprene Adverse Event Insights

367 reports name Fipronil + (S)-Methoprene; 6 recorded a death outcome (1.6% of reported events, not a population-level mortality rate). Active ingredient: Fipronil + (S)-Methoprene. Administration routes: Topical, Unknown, Oral, Cutaneous.

By species: Dog (305 reports), Cat (62 reports). By breed: Retriever - Labrador (41), Domestic Shorthair (24), Dog (unknown) (17).

Leading clinical signs: Emesis (94), Lack of efficacy (ectoparasite) - flea (67), Vomiting (46), Lethargy (see also Central nervous system depression in 'Neurological') (42). Outcome, 367 coded reports: Outcome Unknown leads at 43.1%.

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.