Skin rash or irritation after Levothyroxine in dogs

The FDA has received 137 reports of skin rash or irritation in dogs after Levothyroxine. That is 4.5% of all reports for this medicine, compared with 1.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

137Reports

62%Marked serious

19%Recovered

6.6%Died or euthanised

28 daysTypical onset

How soon it started

Same day

3 3.0%

1–2 days

11 11%

3–7 days

19 19%

1–4 weeks

19 19%

Over a month

47 47%

How the animals did

Recovered

22 16%

Recovered with lasting effects

4 2.9%

Still unwell when reported

49 36%

Died

1 0.7%

Euthanised

8 5.8%

Not known

53 39%

Problems reported at the same time

Itching

51 37%

Hair loss

27 20%

Didn't work as expected

22 16%

21 15%

20 15%

18 13%

15 11%

14 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 skin rash or irritation in dogs?: 137 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 28 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).

Skin rash or irritation with similar medicines

Skin rash or irritation after Trilostane (Vetoryl) 230 reports · 1.9% of its reports
Skin rash or irritation after Insulin 84 reports · 1.1% of its reports
Skin rash or irritation after Phenylpropanolamine (Proin) 40 reports · 1.0% of its reports

All reported side effects of Levothyroxine in dogs · Medicines most reported with skin rash or irritation