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. See the species affected, top reactions, and outcomes below.

36
adverse-event reports
25.0%
death-coded share
Unknown
most-reported species
21
INEFFECTIVE, EUTHANASIA - top reaction
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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 Rate

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 Adverse Event Insights

36 reports name Pentobarbital + Phenytoin; 9 recorded a death outcome (25.0% of reported events, not a population-level mortality rate). Active ingredients: Pentobarbital, Phenytoin. Administration routes: Unknown, Intravenous.

By species: Unknown (22 reports), Dog (11 reports), Cat (2 reports). By breed: Unknown (32), Cat (unknown) (1), Great Pyrenees (1).

Leading clinical signs: INEFFECTIVE, EUTHANASIA (21), Lack of efficacy - NOS (6), Stopper, abnormal (5), INEFFECTIVE, DELAYED EFFECT (3). Outcome, 9 coded reports: Euthanized leads at 100.0%.

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.