Drug profile

The FDA adverse-event record for Cyphenothrin + Fipronil

109 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Cyphenothrin + Fipronil. See the species affected, top reactions, and outcomes below.

109
adverse-event reports
2.8%
death-coded share
Dog
most-reported species
18
Lack of efficacy (ectoparasite) - flea - 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.
109
Total Reports
3
Deaths Reported
2.8%
Death Rate

Active Ingredients

CyphenothrinFipronil

Administration Routes

TopicalOralUnknown

Species Affected

Dog 109

Most Affected Breeds

Retriever - Labrador 13
Retriever - Golden 9
Maltese 8
Bichon Frise 6
Schnauzer - Miniature 5
Crossbred Canine/dog 5
Spaniel - Cocker American 5
Pit Bull 4
Shih Tzu 3
Mastiff 2

Most Reported Reactions

Lack of efficacy (ectoparasite) - flea 18
Vomiting 12
Lack of efficacy (flea) 11
Lethargy (see also Central nervous system depression in 'Neurological') 9
Restlessness 8
Itching 8
Agitation 6
INEFFECTIVE, HOOKS 6
Other abnormal test result NOS 6
Seizure NOS 6
Panting 5
Application site itching 5

Outcome Breakdown

Outcome Unknown
49 (45.0%)
Recovered/Normal
31 (28.4%)
Ongoing
24 (22.0%)
Euthanized
3 (2.8%)
Recovered with Sequela
2 (1.8%)

Cyphenothrin + Fipronil Adverse Event Insights

109 reports name Cyphenothrin + Fipronil; 3 recorded a death outcome (2.8% of reported events, not a population-level mortality rate). Active ingredients: Cyphenothrin, Fipronil. Administration routes: Topical, Oral, Unknown.

By species: Dog (109 reports). By breed: Retriever - Labrador (13), Retriever - Golden (9), Maltese (8).

Leading clinical signs: Lack of efficacy (ectoparasite) - flea (18), Vomiting (12), Lack of efficacy (flea) (11), Lethargy (see also Central nervous system depression in 'Neurological') (9). Outcome, 109 coded reports: Outcome Unknown leads at 45.0%.

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.