Drug profile

The FDA adverse-event record for Pentobarbital + Phenytoin

36 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Pentobarbital + Phenytoin. Species, reactions, and outcomes follow.

#1327 of 2,679
by report volume (all drugs)
36
adverse-event reports
25.0%
death-coded share
Unknown
most-reported species
Verify with FDA CVM →

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Pentobarbital + Phenytoin ranks #1311 of 2679 by total reports (36). Death-coded-share rank requires at least 50 reports. 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)
#1311
This drug, reports of 2679

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. Pentobarbital + Phenytoin has 36 reports now versus 36 in that prior snapshot: 0 the same number of (0.0%).

Report change
+0
Death-coded reports
+0
Death-coded share
+0.0 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 Pentobarbital + Phenytoin changes

Signature read: Pentobarbital + Phenytoin's 25.0% death-coded share is among the highest in the openFDA drug corpus.

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
36
Total Reports
9
Deaths Reported
25.0%
Death-coded share of reports

Active Ingredients

PentobarbitalPhenytoin

Administration Routes

UnknownIntravenous

Species Affected

Unknown 22
Dog 11
Cat 2
Horse 1

Most Affected Breeds

Unknown 32
Cat (unknown) 1
Great Pyrenees 1
Shepherd Dog - German 1
Horse (unknown) 1

Most Reported Reactions

INEFFECTIVE, EUTHANASIA 21
Lack of efficacy - NOS 6
Stopper, abnormal 5
INEFFECTIVE, DELAYED EFFECT 3
Agitation 3
Vials, Damaged 3
Product Defect, General 2
Vials, Leaking 2
Potency, Low 1
Underfilling, Bottles 1
Seizure NOS 1
Open mouth breathing 1

Outcome Breakdown

Euthanized
9 (100.0%)

Pentobarbital + Phenytoin: 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.

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 Pentobarbital + Phenytoin (#1327 of 2,679 by report volume); death-coded 25.0%. PlainBreed drug row · death-coded share stamp 25.0% · 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 →