Drug profile

The FDA adverse-event record for Levothyroxine Sodium Tablets

Name: Levothyroxine Sodium Tablets - FDA Animal Adverse Event Reports
Creator: PlainBreed
License: https://creativecommons.org/publicdomain/zero/1.0/

13 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Levothyroxine Sodium Tablets. See the species affected, top reactions, and outcomes below.

13
adverse-event reports: 15.4%
death-coded share: Dog
most-reported species: 3
Emesis - top reaction

Compiled by PlainBreed Editorial, Pet Health Editorial Team

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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.

Total Reports

Deaths Reported

15.4%

Death Rate

Active Ingredients

Levothyroxine Sodium Tablets

Administration Routes

Oral

Species Affected

Dog 12

Cat 1

Most Affected Breeds

Rottweiler 2

Beagle 1

Mastiff 1

Retriever - Labrador 1

Chihuahua 1

Poodle - Toy 1

Shepherd Dog - Belgian Malinois 1

Poodle - Miniature 1

Domestic Shorthair 1

Siberian Husky 1

Most Reported Reactions

Emesis 3

Lack of efficacy - NOS 3

Vomiting 2

Lethargy (see also Central nervous system depression in 'Neurological') 2

Death by euthanasia 2

Behavioural disorder NOS 2

Lethargy (see also Central nervous system depression in Neurological) 2

Hair coat discolouration 1

Hyperthyroidism 1

Hyperglycaemia 1

Unresponsive to stimuli 1

Application site itching 1

Outcome Breakdown

Recovered/Normal

6 (46.2%)

Outcome Unknown

4 (30.8%)

Euthanized

2 (15.4%)

Ongoing

1 (7.7%)

Levothyroxine Sodium Tablets Adverse Event Insights

13 reports name Levothyroxine Sodium Tablets; 2 recorded a death outcome (15.4% of reported events, not a population-level mortality rate). Active ingredient: Levothyroxine Sodium Tablets. Administration route: Oral.

By species: Dog (12 reports), Cat (1 reports). By breed: Rottweiler (2), Beagle (1), Mastiff (1).

Leading clinical signs: Emesis (3), Lack of efficacy - NOS (3), Vomiting (2), Lethargy (see also Central nervous system depression in 'Neurological') (2). Outcome, 13 coded reports: Recovered/Normal leads at 46.2%.

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.