Eye or vision problems after Levothyroxine in dogs

The FDA has received 25 reports of eye or vision problems in dogs after Levothyroxine. That is 0.8% of all reports for this medicine, compared with 0.7% across reports for all dog medicines.

25Reports

100%Marked serious

24%Recovered

12%Died or euthanised

103 daysTypical onset

How soon it started

Same day

4 19%

1–2 days

2 9.5%

3–7 days

0 0.0%

1–4 weeks

1 4.8%

Over a month

14 67%

How the animals did

Recovered

2 8.0%

Recovered with lasting effects

4 16%

Still unwell when reported

11 44%

Euthanised

3 12%

Not known

5 20%

Problems reported at the same time

Liver problems

7 28%

Tremors

6 24%

Vomiting

6 24%

Abnormal pupil light reflex

5 20%

Lethargy

5 20%

Diarrhea

5 20%

Weight loss

5 20%

Cataract

5 20%

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 eye or vision problems in dogs?: 25 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 103 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).

Eye or vision problems with similar medicines

Eye or vision problems after Trilostane (Vetoryl) 132 reports · 1.1% of its reports
Eye or vision problems after Insulin 227 reports · 3.1% of its reports
Eye or vision problems after Phenylpropanolamine (Proin) 178 reports · 4.3% of its reports

All reported side effects of Levothyroxine in dogs · Medicines most reported with eye or vision problems