Drug profile

The FDA adverse-event record for Fentanyl

717 FDA reports name Fentanyl, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#230 of 2,679
by report volume (all drugs)
717
adverse-event reports
21.9%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Fentanyl ranks #230 of 2679 by total reports (717) and #207 of 1130 by death-coded share (21.9%). National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#230
This drug, reports of 2679
#207
This drug, death share of 1130

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Fentanyl has 717 reports now versus 708 in that prior snapshot: 9 more (1.3%).

Report change
+9
Death-coded reports
+4
Death-coded share
+0.3 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Fentanyl changes

Signature read: death-coded report count at 157 is the most distinctive stamp on Fentanyl's FDA AER row.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
717
Total Reports
157
Deaths Reported
21.9%
Death-coded share of reports

Active Ingredients

Fentanyl

Administration Routes

TransdermalUnknownTopicalIntravenousOtherCutaneousIntramuscularOralParenteralIntradermal

Species Affected

Dog 614
Cat 72
Unknown 12
Human 9
Goat 3
Primate 2
Alpaca 2
Pig 2
Guinea Pig 1

Most Affected Breeds

Dog (unknown) 86
Retriever - Labrador 77
Domestic Shorthair 39
Crossbred Canine/dog 31
Unknown 24
Retriever - Golden 21
Dachshund (unspecified) 19
Chihuahua 19
Pit Bull 18
Boxer (German Boxer) 15

Most Reported Reactions

Anorexia 150
Vocalisation 112
Death by euthanasia 93
Hypothermia 90
Vomiting 89
Lethargy (see also Central nervous system depression in 'Neurological') 86
Sedation 86
Not eating 79
Other abnormal test result NOS 68
Lack of efficacy - NOS 65
Diarrhoea 62
Inappetence 62

Outcome Breakdown

Recovered/Normal
291 (41.4%)
Outcome Unknown
152 (21.6%)
Euthanized
92 (13.1%)
Ongoing
79 (11.2%)
Died
66 (9.4%)
Recovered with Sequela
23 (3.3%)

Fentanyl: high death-coded share in the FDA AER row

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.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Fentanyl, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar death-coded share

Nearest other drugs by death-coded share (21.9% here), distinct from the volume row.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Fentanyl (#230 of 2,679 by report volume); death-coded 21.9%. PlainBreed drug row · death-coded report count stamp 157 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →