Drug profile

The FDA adverse-event record for Diphenhydramine Injection

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

25
adverse-event reports
4.0%
death-coded share
Dog
most-reported species
9
Vomiting - 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.
25
Total Reports
1
Deaths Reported
4.0%
Death Rate

Active Ingredients

Diphenhydramine Injection

Administration Routes

UnknownSubcutaneousIntramuscular

Species Affected

Dog 20
Cat 5

Most Affected Breeds

Domestic Shorthair 4
Coton de Tuléar 3
Bulldog - French 3
Crossbred Canine/dog 2
Dachshund (unspecified) 2
Terrier - Boston 2
Terrier (unspecified) 2
Shih Tzu 1
Terrier - Bull - Staffordshire 1
Russian 1

Most Reported Reactions

Vomiting 9
Lethargy (see also Central nervous system depression in 'Neurological') 4
Blepharospasm 4
Corneal ulcer 4
Keratoconjunctivitis sicca 4
Schirmer tear test 4
Cranial nerve disorder 4
Dry nose 4
Keratitis 4
Hyperaemia 4
Anaphylaxis 4
Lethargy (see also Central nervous system depression in Neurological) 4

Outcome Breakdown

Recovered/Normal
10 (40.0%)
Outcome Unknown
7 (28.0%)
Ongoing
7 (28.0%)
Euthanized
1 (4.0%)

Diphenhydramine Injection Adverse Event Insights

25 reports name Diphenhydramine Injection; 1 recorded a death outcome (4.0% of reported events, not a population-level mortality rate). Active ingredient: Diphenhydramine Injection. Administration routes: Unknown, Subcutaneous, Intramuscular.

By species: Dog (20 reports), Cat (5 reports). By breed: Domestic Shorthair (4), Coton de Tuléar (3), Bulldog - French (3).

Leading clinical signs: Vomiting (9), Lethargy (see also Central nervous system depression in 'Neurological') (4), Blepharospasm (4), Corneal ulcer (4). Outcome, 25 coded reports: Recovered/Normal leads at 40.0%.

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.