Drug profile

The FDA adverse-event record for Clemastine

25 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Clemastine. Species, reactions, and outcomes follow.

#1582 of 2,679
by report volume (all drugs)
25
adverse-event reports
4.0%
death-coded share
Dog
most-reported species
Verify with FDA CVM →

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Clemastine ranks #1577 of 2679 by total reports (25). Death-coded-share rank requires at least 50 reports. National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#1577
This drug, reports of 2679

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Clemastine has 25 reports now versus 25 in that prior snapshot: 0 the same number of (0.0%).

Report change
+0
Death-coded reports
+0
Death-coded share
+0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Clemastine changes

Signature read: Clemastine's 4.0% death-coded share is among the lowest in the openFDA drug corpus.

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-coded share of reports

Active Ingredients

Clemastine

Administration Routes

OralUnknown

Species Affected

Dog 23
Cat 2

Most Affected Breeds

Shih Tzu 3
Retriever - Labrador 2
Maltese 2
Mixed (Dog) 1
Whippet 1
Dachshund (unspecified) 1
Corgi (unspecified) 1
Terrier - Cairn 1
Domestic Shorthair 1
Siberian Husky 1

Most Reported Reactions

Lethargy (see also Central nervous system depression in 'Neurological') 7
Other abnormal test result NOS 7
Vomiting 5
Emesis 5
Behavioural disorder NOS 3
INEFFECTIVE, ATOPY CONTROL 2
Abnormal ultrasound finding 2
Abnormal radiograph finding 2
Diarrhoea 2
Inappetence 2
Pruritus 2
Weight loss 2

Outcome Breakdown

Recovered/Normal
11 (44.0%)
Ongoing
7 (28.0%)
Outcome Unknown
5 (20.0%)
Recovered with Sequela
1 (4.0%)
Euthanized
1 (4.0%)

Clemastine: low death-coded share in the FDA AER row

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.

What to do with this drug

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Clemastine (#1582 of 2,679 by report volume); death-coded 4.0%. PlainBreed drug row · death-coded share stamp 4.0% · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →