Drug profile

The FDA adverse-event record for Fentanyl

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

694
adverse-event reports
21.2%
death-coded share
Dog
most-reported species
149
Anorexia - 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.
694
Total Reports
147
Deaths Reported
21.2%
Death Rate

Active Ingredients

Fentanyl

Administration Routes

TransdermalUnknownTopicalIntravenousOtherCutaneousIntramuscularOralIntradermalParenteral

Species Affected

Dog 597
Cat 66
Unknown 12
Human 9
Goat 3
Primate 2
Alpaca 2
Pig 2
Guinea Pig 1

Most Affected Breeds

Dog (unknown) 86
Retriever - Labrador 75
Domestic Shorthair 34
Crossbred Canine/dog 31
Unknown 24
Retriever - Golden 20
Dachshund (unspecified) 18
Chihuahua 18
Pit Bull 18
Boxer (German Boxer) 15

Most Reported Reactions

Anorexia 149
Vocalisation 112
Hypothermia 90
Vomiting 87
Death by euthanasia 87
Lethargy (see also Central nervous system depression in 'Neurological') 86
Sedation 85
Not eating 74
Other abnormal test result NOS 65
Lack of efficacy - NOS 64
Inappetence 62
Diarrhoea 59

Outcome Breakdown

Recovered/Normal
288 (42.4%)
Outcome Unknown
144 (21.2%)
Euthanized
86 (12.6%)
Ongoing
77 (11.3%)
Died
62 (9.1%)
Recovered with Sequela
23 (3.4%)

Fentanyl Adverse Event Insights

694 reports name Fentanyl; 147 recorded a death outcome (21.2% of reported events, not a population-level mortality rate). Active ingredient: Fentanyl. Administration routes: Transdermal, Unknown, Topical, Intravenous.

By species: Dog (597 reports), Cat (66 reports), Unknown (12 reports). By breed: Dog (unknown) (86), Retriever - Labrador (75), Domestic Shorthair (34).

Leading clinical signs: Anorexia (149), Vocalisation (112), Hypothermia (90), Vomiting (87). Outcome, 680 coded reports: Recovered/Normal leads at 42.4%.

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.