Abnormal radiograph finding after Levothyroxine in dogs

The FDA has received 79 reports of abnormal radiograph finding in dogs after Levothyroxine. That is 2.6% of all reports for this medicine, compared with 0.9% across reports for all dog medicines, so it is reported unusually often with this medicine.

79Reports

87%Marked serious

15%Recovered

30%Died or euthanised

47 daysTypical onset

How soon it started

Same day

5 9.6%

1–2 days

8 15%

3–7 days

2 3.8%

1–4 weeks

7 13%

Over a month

30 58%

How the animals did

Recovered

10 13%

Recovered with lasting effects

2 2.5%

Still unwell when reported

35 44%

Died

6 7.6%

Euthanised

18 23%

Not known

8 10%

Problems reported at the same time

30 38%

29 37%

28 35%

27 34%

24 30%

23 29%

18 23%

Abnormal ultrasound finding

18 23%

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 abnormal radiograph finding in dogs?: 79 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 47 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).

Abnormal radiograph finding with similar medicines

Abnormal radiograph finding after Trilostane (Vetoryl) 235 reports · 2.0% of its reports
Abnormal radiograph finding after Insulin 52 reports · 0.7% of its reports
Abnormal radiograph finding after Phenylpropanolamine (Proin) 37 reports · 0.9% of its reports

All reported side effects of Levothyroxine in dogs · Medicines most reported with abnormal radiograph finding