Drug profile

The FDA adverse-event record for Fipronil 10%/S Methoprene 12% Spot On

47 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Fipronil 10%/S Methoprene 12% Spot On. See the species affected, top reactions, and outcomes below.

47
adverse-event reports
4.3%
death-coded share
Cat
most-reported species
14
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.
47
Total Reports
2
Deaths Reported
4.3%
Death Rate

Active Ingredients

Fipronil 10%/S Methoprene 12% Spot On

Administration Routes

TopicalUnknownOther

Species Affected

Cat 43
Dog 4

Most Affected Breeds

Domestic Shorthair 24
Domestic Mediumhair 6
Cat (unknown) 5
Mixed (Cat) 2
Unknown 1
Himalayan 1
Retriever - Labrador 1
Spaniel - King Charles Cavalier 1
Crossbred Canine/dog 1
Havanese 1

Most Reported Reactions

Lack of efficacy (ectoparasite) - flea 14
Application site hair loss 7
Lethargy (see also Central nervous system depression in 'Neurological') 6
Vomiting 6
Application site irritation 4
Hair loss NOS 4
Behavioural disorder NOS 3
Scratching 3
Reddening of the skin 3
Skin sore 2
Application site ulcer 2
Application site hair change 2

Outcome Breakdown

Outcome Unknown
30 (63.8%)
Recovered/Normal
8 (17.0%)
Ongoing
7 (14.9%)
Euthanized
1 (2.1%)
Died
1 (2.1%)

Fipronil 10%/S Methoprene 12% Spot On Adverse Event Insights

47 reports name Fipronil 10%/S Methoprene 12% Spot On; 2 recorded a death outcome (4.3% of reported events, not a population-level mortality rate). Active ingredient: Fipronil 10%/S Methoprene 12% Spot On. Administration routes: Topical, Unknown, Other.

By species: Cat (43 reports), Dog (4 reports). By breed: Domestic Shorthair (24), Domestic Mediumhair (6), Cat (unknown) (5).

Leading clinical signs: Lack of efficacy (ectoparasite) - flea (14), Application site hair loss (7), Lethargy (see also Central nervous system depression in 'Neurological') (6), Vomiting (6). Outcome, 47 coded reports: Outcome Unknown leads at 63.8%.

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.