Drug profile

The FDA adverse-event record for Phenobarbital

1,618 FDA reports name Phenobarbital, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#131 of 2,679
by report volume (all drugs)
1,618
adverse-event reports
12.3%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Phenobarbital ranks #131 of 2679 by total reports (1,618) and #448 of 1130 by death-coded share (12.3%). 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)
#131
This drug, reports of 2679
#448
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. Phenobarbital has 1,618 reports now versus 1,591 in that prior snapshot: 27 more (1.7%).

Report change
+27
Death-coded reports
+2
Death-coded share
−0.1 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 Phenobarbital changes

Signature read: death-coded report count at 199 is the most distinctive stamp on Phenobarbital'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.
1,618
Total Reports
199
Deaths Reported
12.3%
Death-coded share of reports

Active Ingredients

Phenobarbital

Administration Routes

OralUnknownIntravenousRectalSubcutaneousOtherParenteral

Species Affected

Dog 1,488
Cat 123
Unknown 6
Other Canids 1

Most Affected Breeds

Retriever - Labrador 130
Chihuahua 89
Domestic Shorthair 69
Retriever - Golden 64
Crossbred Canine/dog 61
Shepherd Dog - German 54
Dog (unknown) 50
Terrier - Yorkshire 46
Shepherd Dog - Australian 45
Beagle 43

Most Reported Reactions

Seizure NOS 612
Lethargy (see also Central nervous system depression in 'Neurological') 181
Vomiting 161
Death by euthanasia 117
Other abnormal test result NOS 110
Lack of efficacy - NOS 96
Ataxia 94
Emesis 93
Diarrhoea 89
Death 81
Behavioural disorder NOS 77
Anorexia 75

Outcome Breakdown

Recovered/Normal
486 (30.3%)
Ongoing
470 (29.3%)
Outcome Unknown
386 (24.0%)
Euthanized
112 (7.0%)
Died
87 (5.4%)
Recovered with Sequela
65 (4.0%)

Phenobarbital: high report volume 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 Phenobarbital, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

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 Phenobarbital (#131 of 2,679 by report volume); death-coded 12.3%. PlainBreed drug row · death-coded report count stamp 199 · 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 →