Drug profile

The FDA adverse-event record for Alfaxalone

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

#182 of 2,679
by report volume (all drugs)
996
adverse-event reports
19.2%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Alfaxalone ranks #182 of 2679 by total reports (996) and #255 of 1130 by death-coded share (19.2%). 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)
#182
This drug, reports of 2679
#255
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. Alfaxalone has 996 reports now versus 957 in that prior snapshot: 39 more (4.1%).

Report change
+39
Death-coded reports
+1
Death-coded share
−0.7 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 Alfaxalone changes

Signature read: death-coded report count at 191 is the most distinctive stamp on Alfaxalone'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.
996
Total Reports
191
Deaths Reported
19.2%
Death-coded share of reports

Active Ingredients

Alfaxalone

Administration Routes

IntravenousUnknownIntramuscularSubcutaneousParenteralOralTopicalIntraperitonealIntrauterineOphthalmic

Species Affected

Dog 479
Cat 457
Rabbit 22
Unknown 13
Guinea Pig 4
Human 4
Other Reptiles 2
Mouse 2
Lizard 2
Ferret 2

Most Affected Breeds

Domestic Shorthair 227
Unknown 83
Domestic Longhair 44
Retriever - Labrador 42
Chihuahua 37
Domestic Mediumhair 26
Dog (unknown) 24
Cat (other) 23
Cat (unknown) 22
Shih Tzu 20

Most Reported Reactions

Death 141
Cardiac arrest 76
Bradycardia 76
Not eating 73
Lack of efficacy - NOS 69
Vomiting 65
Diarrhoea 53
Hypotension 53
Seizure NOS 52
Tachycardia 51
Apnoea 49
Vocalisation 48

Outcome Breakdown

Recovered/Normal
463 (46.4%)
Ongoing
207 (20.8%)
Died
152 (15.2%)
Outcome Unknown
126 (12.6%)
Euthanized
40 (4.0%)
Recovered with Sequela
9 (0.9%)

Alfaxalone: 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 Alfaxalone, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar death-coded share

Nearest other drugs by death-coded share (19.2% 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 Alfaxalone (#182 of 2,679 by report volume); death-coded 19.2%. PlainBreed drug row · death-coded report count stamp 191 · 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 →