Excessive thirst after Methimazole in cats

27 reports to the FDA describe excessive thirst in cats given Methimazole. That is 1.5% of all reports for this medicine, compared with 1.0% across reports for all cat medicines, so it is reported unusually often with this medicine.

27Reports

44%Marked serious

7.4%Recovered

15%Died or euthanised

12 daysTypical onset

How soon it started

Same day

5 25%

1–2 days

4 20%

3–7 days

1 5.0%

1–4 weeks

3 15%

Over a month

7 35%

How the animals did

Recovered

2 7.4%

Still unwell when reported

7 26%

Died

2 7.4%

Euthanised

2 7.4%

Not known

14 52%

Problems reported at the same time

17 63%

10 37%

9 33%

7 26%

7 26%

Didn't work as expected

5 19%

Liver problems

4 15%

Death

4 15%

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 excessive thirst in cats?: 27 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 12 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).

Excessive thirst with similar medicines

Excessive thirst after Velagliflozin (Senvelgo) 158 reports · 3.3% of its reports
Excessive thirst after Bexagliflozin (Bexacat) 230 reports · 5.7% of its reports
Excessive thirst after Insulin 166 reports · 4.4% of its reports

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