Application site reaction after Methimazole in cats

The FDA has received 34 reports of application site reaction in cats after Methimazole. That is 1.9% of all reports for this medicine, compared with 8.1% across reports for all cat medicines, so it is reported less often than average with this medicine.

34Reports

29%Marked serious

32%Recovered

2.9%Died or euthanised

30 daysTypical onset

How soon it started

Same day

2 10%

1–2 days

1 5.0%

3–7 days

1 5.0%

1–4 weeks

7 35%

Over a month

9 45%

How the animals did

Recovered

10 29%

Recovered with lasting effects

1 2.9%

Still unwell when reported

8 24%

Died

1 2.9%

Not known

14 41%

Problems reported at the same time

8 24%

5 15%

5 15%

4 12%

4 12%

Pinnae disorder

3 8.8%

Behaviour change

3 8.8%

Vomiting

3 8.8%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Methimazole treats an overactive thyroid in cats.

Questions owners ask

Can Methimazole cause application site reaction in cats?: 34 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 30 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).

All reported side effects of Methimazole in cats · Medicines most reported with application site reaction