Loss of appetite after Methimazole in cats

471 reports to the FDA describe loss of appetite in cats given Methimazole. That is 26% of all reports for this medicine, compared with 14% across reports for all cat medicines, so it is reported unusually often with this medicine.

471Reports

57%Marked serious

17%Recovered

19%Died or euthanised

16 daysTypical onset

How soon it started

Same day

56 15%

1–2 days

46 13%

3–7 days

28 7.7%

1–4 weeks

119 33%

Over a month

114 31%

How the animals did

Recovered

75 16%

Recovered with lasting effects

4 0.8%

Still unwell when reported

130 28%

Died

42 8.9%

Euthanised

49 10%

Not known

171 36%

Problems reported at the same time

200 42%

160 34%

122 26%

88 19%

77 16%

69 15%

58 12%

47 10.0%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

364

About this medicine

Methimazole treats an overactive thyroid in cats.

Questions owners ask

Can Methimazole cause loss of appetite in cats?: 471 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 16 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).

Loss of appetite with similar medicines

Loss of appetite after Velagliflozin (Senvelgo) 917 reports · 19% of its reports
Loss of appetite after Bexagliflozin (Bexacat) 754 reports · 19% of its reports
Loss of appetite after Insulin 488 reports · 13% of its reports

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