Drug profile

The FDA adverse-event record for Diphenhydramine Injectable

11 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Diphenhydramine Injectable. See the species affected, top reactions, and outcomes below.

11
adverse-event reports
18.2%
death-coded share
Dog
most-reported species
6
Vomiting - top reaction
Verify with FDA CVM →
Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
11
Total Reports
2
Deaths Reported
18.2%
Death Rate

Active Ingredients

Diphenhydramine Injectable

Administration Routes

UnknownIntramuscular

Species Affected

Dog 8
Cat 3

Most Affected Breeds

Domestic Shorthair 3
Shepherd Dog - Australian 1
Pug 1
Shih Tzu 1
Doberman Pinscher 1
Terrier - Rat 1
Poodle - Miniature 1
Terrier - Boston 1
Crossbred Canine/dog 1

Most Reported Reactions

Vomiting 6
Lethargy (see also Central nervous system depression in 'Neurological') 4
Diarrhoea 3
Anaphylaxis 3
Other abnormal test result NOS 2
Anaemia NOS 2
Emesis (multiple) 2
Weight loss 2
Drooling 2
Lack of efficacy - NOS 2
Facial swelling (see also Skin) 2
Oral ulceration 1

Outcome Breakdown

Ongoing
6 (54.5%)
Recovered/Normal
2 (18.2%)
Euthanized
1 (9.1%)
Died
1 (9.1%)
Outcome Unknown
1 (9.1%)

Diphenhydramine Injectable Adverse Event Insights

11 reports name Diphenhydramine Injectable; 2 recorded a death outcome (18.2% of reported events, not a population-level mortality rate). Active ingredient: Diphenhydramine Injectable. Administration routes: Unknown, Intramuscular.

By species: Dog (8 reports), Cat (3 reports). By breed: Domestic Shorthair (3), Shepherd Dog - Australian (1), Pug (1).

Leading clinical signs: Vomiting (6), Lethargy (see also Central nervous system depression in 'Neurological') (4), Diarrhoea (3), Anaphylaxis (3). Outcome, 11 coded reports: Ongoing leads at 54.5%.

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.