Drug profile

The FDA adverse-event record for Pentobarbital, Phenytoin

185 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Pentobarbital, Phenytoin. See the species affected, top reactions, and outcomes below.

185
adverse-event reports
74.6%
death-coded share
Dog
most-reported species
80
Death by 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.
185
Total Reports
138
Deaths Reported
74.6%
Death Rate

Active Ingredients

Pentobarbital, Phenytoin

Administration Routes

IntravenousUnknownSubcutaneousOralTopicalOtherOphthalmicIntracardiacIntraperitonealIntramuscular

Species Affected

Dog 100
Cat 34
Unknown 20
Human 16
Horse 10
Other 2
Sheep 1
Rabbit 1
Cattle 1

Most Affected Breeds

Unknown 38
Mixed (Dog) 28
Dog (unknown) 25
Domestic (unspecified) 15
Crossbred Canine/dog 13
Cat (unknown) 13
Retriever - Labrador 9
Shepherd Dog - German 4
Rottweiler 4
Mixed (Horse) 3

Most Reported Reactions

Death by euthanasia 80
INEFFECTIVE, EUTHANASIA 74
INEFFECTIVE, DELAYED EFFECT 64
Unclassifiable adverse event 23
Accidental exposure 22
Injection site pain 8
Vocalisation 7
Solution, Abnormal 6
Vials, Damaged 5
Vials, Abnormal 5
Hypothermia 4
Eye irritation 4

Outcome Breakdown

Died
132 (95.0%)
Euthanized
6 (4.3%)
Outcome Unknown
1 (0.7%)

Pentobarbital, Phenytoin Adverse Event Insights

185 reports name Pentobarbital, Phenytoin; 138 recorded a death outcome (74.6% of reported events, not a population-level mortality rate). Active ingredient: Pentobarbital, Phenytoin. Administration routes: Intravenous, Unknown, Subcutaneous, Oral.

By species: Dog (100 reports), Cat (34 reports), Unknown (20 reports). By breed: Unknown (38), Mixed (Dog) (28), Dog (unknown) (25).

Leading clinical signs: Death by euthanasia (80), INEFFECTIVE, EUTHANASIA (74), INEFFECTIVE, DELAYED EFFECT (64), Unclassifiable adverse event (23). Outcome, 139 coded reports: Died leads at 95.0%.

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.