Reddening of the skin after Levothyroxine in dogs

44 reports to the FDA describe reddening of the skin in dogs given Levothyroxine. That is 1.5% of all reports for this medicine, compared with 0.4% across reports for all dog medicines, so it is reported unusually often with this medicine.

44Reports

52%Marked serious

50%Recovered

0.0%Died or euthanised

22 daysTypical onset

How soon it started

Same day

1 2.9%

1–2 days

4 12%

3–7 days

6 18%

1–4 weeks

11 32%

Over a month

12 35%

How the animals did

Recovered

19 43%

Recovered with lasting effects

3 6.8%

Still unwell when reported

13 30%

Not known

9 20%

Problems reported at the same time

Itching

20 45%

Skin rash or irritation

13 30%

Hair loss

12 27%

Diarrhea

7 16%

Didn't work as expected

6 14%

Overdose

5 11%

Skin redness

4 9.1%

Flaking skin

4 9.1%

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 reddening of the skin in dogs?: 44 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 22 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).

Reddening of the skin with similar medicines

Reddening of the skin after Trilostane (Vetoryl) 51 reports · 0.4% of its reports
Reddening of the skin after Phenylpropanolamine (Proin) 54 reports · 1.3% of its reports

All reported side effects of Levothyroxine in dogs · Medicines most reported with reddening of the skin