Drug profile

The FDA adverse-event record for Capstar

52 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Capstar. See the species affected, top reactions, and outcomes below.

52
adverse-event reports
9.6%
death-coded share
Dog
most-reported species
21
Lack of efficacy (ectoparasite) - flea - top reaction
Verify with FDA CVM →
Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
52
Total Reports
5
Deaths Reported
9.6%
Death Rate

Active Ingredients

Capstar

Administration Routes

OralUnknownTopical

Species Affected

Dog 39
Cat 13

Most Affected Breeds

Domestic Shorthair 5
Cat (other) 4
Retriever - Labrador 3
Shepherd Dog - German 3
Retriever - Golden 2
Crossbred Canine/dog 2
Cat (unknown) 2
Terrier - Yorkshire 2
Dog (unknown) 2
Terrier - Bull - American Pit 2

Most Reported Reactions

Lack of efficacy (ectoparasite) - flea 21
Seizure NOS 5
Lethargy (see also Central nervous system depression in Neurological) 5
Vomiting 4
Lack of efficacy (ectoparasite) - NOS 3
Death by euthanasia 3
Weight loss 3
Emesis (multiple) 2
Behavioural disorder NOS 2
Hair loss NOS 2
Lethargy (see also Central nervous system depression in 'Neurological') 2
Decreased appetite 2

Outcome Breakdown

Ongoing
24 (46.2%)
Outcome Unknown
14 (26.9%)
Recovered/Normal
9 (17.3%)
Euthanized
3 (5.8%)
Died
2 (3.8%)

Capstar Adverse Event Insights

52 reports name Capstar; 5 recorded a death outcome (9.6% of reported events, not a population-level mortality rate). Active ingredient: Capstar. Administration routes: Oral, Unknown, Topical.

By species: Dog (39 reports), Cat (13 reports). By breed: Domestic Shorthair (5), Cat (other) (4), Retriever - Labrador (3).

Leading clinical signs: Lack of efficacy (ectoparasite) - flea (21), Seizure NOS (5), Lethargy (see also Central nervous system depression in Neurological) (5), Vomiting (4). Outcome, 52 coded reports: Ongoing leads at 46.2%.

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.