Drug profile

The FDA adverse-event record for Thyroid Supplementation

27 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Thyroid Supplementation. See the species affected, top reactions, and outcomes below.

27
adverse-event reports
18.5%
death-coded share
Dog
most-reported species
5
Underdose - 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.
27
Total Reports
5
Deaths Reported
18.5%
Death Rate

Active Ingredients

Thyroid Supplementation

Administration Routes

OralUnknown

Species Affected

Dog 26
Cat 1

Most Affected Breeds

Crossbred Canine/dog 5
Chihuahua 4
Dog (other) 3
Beagle 3
Retriever - Golden 2
Doberman Pinscher 2
Retriever - Labrador 2
Maltese 1
Boxer (German Boxer) 1
Bulldog 1

Most Reported Reactions

Underdose 5
Elevated serum alkaline phosphatase (SAP) 5
Elevated alanine aminotransferase (ALT) 5
Malaise 4
Death by euthanasia 3
Weight loss 3
Polyuria 3
Muscle weakness NOS 3
Lethargy (see also Central nervous system depression in Neurological) 3
Lethargy (see also Central nervous system depression in 'Neurological') 2
Diarrhoea 2
Panting 2

Outcome Breakdown

Outcome Unknown
11 (40.7%)
Recovered/Normal
6 (22.2%)
Ongoing
5 (18.5%)
Euthanized
3 (11.1%)
Died
2 (7.4%)

Thyroid Supplementation Adverse Event Insights

27 reports name Thyroid Supplementation; 5 recorded a death outcome (18.5% of reported events, not a population-level mortality rate). Active ingredient: Thyroid Supplementation. Administration routes: Oral, Unknown.

By species: Dog (26 reports), Cat (1 reports). By breed: Crossbred Canine/dog (5), Chihuahua (4), Dog (other) (3).

Leading clinical signs: Underdose (5), Elevated serum alkaline phosphatase (SAP) (5), Elevated alanine aminotransferase (ALT) (5), Malaise (4). Outcome, 27 coded reports: Outcome Unknown leads at 40.7%.

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.