Otitis externa after Levothyroxine in dogs

24 reports to the FDA describe otitis externa in dogs given Levothyroxine. That is 0.8% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

24Reports

58%Marked serious

13%Recovered

17%Died or euthanised

70 daysTypical onset

How soon it started

Same day

1 5.6%

1–2 days

2 11%

3–7 days

1 5.6%

1–4 weeks

3 17%

Over a month

11 61%

How the animals did

Recovered

2 8.3%

Recovered with lasting effects

1 4.2%

Still unwell when reported

8 33%

Euthanised

4 17%

Not known

9 38%

Problems reported at the same time

Itching

9 38%

Didn't work as expected

8 33%

7 29%

5 21%

5 21%

4 17%

4 17%

Skin rash or irritation

4 17%

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 otitis externa in dogs?: 24 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 70 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).

Otitis externa with similar medicines

Otitis externa after Trilostane (Vetoryl) 28 reports · 0.2% of its reports
Otitis externa after Insulin 33 reports · 0.4% of its reports

All reported side effects of Levothyroxine in dogs · Medicines most reported with otitis externa