Drug profile

The FDA adverse-event record for Unknown Antihistamine

12 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Unknown Antihistamine. See the species affected, top reactions, and outcomes below.

12
adverse-event reports
8.3%
death-coded share
Dog
most-reported species
3
Other abnormal test result NOS - 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.
12
Total Reports
1
Deaths Reported
8.3%
Death Rate

Active Ingredients

Unknown Antihistamine

Administration Routes

OralUnknownIntramuscular

Species Affected

Dog 12

Most Affected Breeds

Pug 3
Bichon Frise 2
Bulldog 2
Shih Tzu 1
Poodle - Toy 1
Retriever - Labrador 1
Chihuahua 1
Dachshund - Miniature 1

Most Reported Reactions

Other abnormal test result NOS 3
Vomiting 3
Seizure NOS 3
Pruritus 2
Lethargy (see also Central nervous system depression in 'Neurological') 2
Loose stool 2
Lack of efficacy (ectoparasite) - flea 2
Stumbling gait 2
Mental impairment NOS 2
Proprioception loss 2
Papillomatosis 1
Splenic neoplasm 1

Outcome Breakdown

Outcome Unknown
5 (41.7%)
Recovered/Normal
5 (41.7%)
Recovered with Sequela
1 (8.3%)
Euthanized
1 (8.3%)

Unknown Antihistamine Adverse Event Insights

12 reports name Unknown Antihistamine; 1 recorded a death outcome (8.3% of reported events, not a population-level mortality rate). Active ingredient: Unknown Antihistamine. Administration routes: Oral, Unknown, Intramuscular.

By species: Dog (12 reports). By breed: Pug (3), Bichon Frise (2), Bulldog (2).

Leading clinical signs: Other abnormal test result NOS (3), Vomiting (3), Seizure NOS (3), Pruritus (2). Outcome, 12 coded reports: Outcome Unknown leads at 41.7%.

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.