Itching after Methimazole in cats

235 reports to the FDA describe itching in cats given Methimazole. That is 13% of all reports for this medicine, compared with 8.9% across reports for all cat medicines.

235Reports

55%Marked serious

25%Recovered

3.4%Died or euthanised

24 daysTypical onset

How soon it started

Same day

19 10%

1–2 days

16 8.7%

3–7 days

14 7.7%

1–4 weeks

55 30%

Over a month

79 43%

How the animals did

Recovered

58 25%

Recovered with lasting effects

1 0.4%

Still unwell when reported

98 42%

Died

2 0.9%

Euthanised

6 2.6%

Not known

70 30%

Problems reported at the same time

Hair loss

54 23%

Vomiting

41 17%

Skin scab

39 17%

Skin rash or irritation

37 16%

36 15%

28 12%

24 10%

19 8.1%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

191

About this medicine

Methimazole treats an overactive thyroid in cats.

Questions owners ask

Can Methimazole cause itching in cats?: 235 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 24 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).

Itching with similar medicines

Itching after Bexagliflozin (Bexacat) 25 reports · 0.6% of its reports
Itching after Insulin 124 reports · 3.3% of its reports

All reported side effects of Methimazole in cats · Medicines most reported with itching