Drug profile

The FDA adverse-event record for Imidacloprid + Pyriproxyfen

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

699
adverse-event reports
5.7%
death-coded share
Cat
most-reported species
221
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.
699
Total Reports
40
Deaths Reported
5.7%
Death Rate

Active Ingredients

ImidaclopridImidacloprid + PyriproxyfenPyriproxyfen

Administration Routes

TopicalUnknownOralOtherIntraocular

Species Affected

Cat 494
Dog 198
Human 5
Rabbit 1
Unknown 1

Most Affected Breeds

Domestic Shorthair 250
Cat (unknown) 89
Domestic Longhair 56
Domestic Mediumhair 39
Pit Bull 20
Terrier - Yorkshire 17
Maine Coon 17
Dog (unknown) 17
Siamese 13
Chihuahua 13

Most Reported Reactions

Lack of efficacy (ectoparasite) - flea 221
Pruritus 214
Behavioural disorder NOS 82
Lethargy (see also Central nervous system depression in 'Neurological') 82
Vomiting 71
Lack of efficacy (endoparasite) - tapeworm 40
Weight loss 37
Application site alopecia 33
Skin lesion NOS 33
Application site pruritus 29
Anorexia 28
Vocalisation 28

Outcome Breakdown

Outcome Unknown
425 (60.9%)
Recovered/Normal
154 (22.1%)
Ongoing
78 (11.2%)
Died
27 (3.9%)
Euthanized
13 (1.9%)
Recovered with Sequela
1 (0.1%)

Imidacloprid + Pyriproxyfen Adverse Event Insights

699 reports name Imidacloprid + Pyriproxyfen; 40 recorded a death outcome (5.7% of reported events, not a population-level mortality rate). Active ingredients: Imidacloprid, Imidacloprid + Pyriproxyfen, Pyriproxyfen. Administration routes: Topical, Unknown, Oral, Other.

By species: Cat (494 reports), Dog (198 reports), Human (5 reports). By breed: Domestic Shorthair (250), Cat (unknown) (89), Domestic Longhair (56).

Leading clinical signs: Lack of efficacy (ectoparasite) - flea (221), Pruritus (214), Behavioural disorder NOS (82), Lethargy (see also Central nervous system depression in 'Neurological') (82). Outcome, 698 coded reports: Outcome Unknown leads at 60.9%.

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.