Musculoskeletal disorder after Levothyroxine in dogs

The FDA has received 30 reports of musculoskeletal disorder in dogs after Levothyroxine. That is 1.0% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

30Reports

70%Marked serious

13%Recovered

30%Died or euthanised

127 daysTypical onset

How soon it started

Same day

2 17%

1–2 days

1 8.3%

3–7 days

0 0.0%

1–4 weeks

2 17%

Over a month

7 58%

How the animals did

Recovered

4 13%

Still unwell when reported

12 40%

Died

3 10%

Euthanised

6 20%

Not known

5 17%

Problems reported at the same time

8 27%

8 27%

6 20%

5 17%

5 17%

4 13%

4 13%

3 10%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Levothyroxine treats an underactive thyroid.

Questions owners ask

Can Levothyroxine cause musculoskeletal disorder in dogs?: 30 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 127 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Musculoskeletal disorder with similar medicines

Musculoskeletal disorder after Trilostane (Vetoryl) 55 reports · 0.5% of its reports
Musculoskeletal disorder after Insulin 22 reports · 0.3% of its reports
Musculoskeletal disorder after Phenylpropanolamine (Proin) 20 reports · 0.5% of its reports

All reported side effects of Levothyroxine in dogs · Medicines most reported with musculoskeletal disorder