Drug profile

The FDA adverse-event record for Transdermal Methimazole

18 FDA reports name Transdermal Methimazole, a lower-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#1929 of 2,679
by report volume (all drugs)
18
adverse-event reports
0.0%
death-coded share
Cat
most-reported species
Verify with FDA CVM →

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Transdermal Methimazole ranks #1884 of 2679 by total reports (18). 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)
#1884
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. Transdermal Methimazole has 18 reports now versus 16 in that prior snapshot: 2 more (12.5%).

Report change
+2
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 Transdermal Methimazole changes

Signature read: Transdermal Methimazole's 0.0% 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.
18
Total Reports
0
Deaths Reported
0.0%
Death-coded share of reports

Active Ingredients

Transdermal Methimazole

Administration Routes

TransdermalTopicalUnknown

Species Affected

Cat 18

Most Affected Breeds

Domestic Shorthair 10
Domestic Longhair 3
Cat (unknown) 2
Cat (other) 1
Domestic Mediumhair 1
Oriental 1

Most Reported Reactions

Weight loss 4
Intentional misuse 4
Skin lesion NOS 3
Lethargy (see also Central nervous system depression in Neurological) 3
Decreased appetite 3
Inappropriate urination 3
Skin scab 2
Vomiting 2
Ocular discharge 2
Emesis (multiple) 2
Inappetence 1
Pruritus 1

Outcome Breakdown

Outcome Unknown
8 (44.4%)
Ongoing
8 (44.4%)
Recovered/Normal
2 (11.1%)

Transdermal Methimazole: 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 Transdermal Methimazole (#1929 of 2,679 by report volume); death-coded 0.0%. PlainBreed drug row · death-coded share stamp 0.0% · 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 →