Methimazole and weight gain

[Hypergirl77]

I'm on 20mg/once a day of methimazole for the time-being and have been since late September. I seem to be very gradually gaining weight (about 1 and a-half pounds since Oct. 1), which could be from overeating, but I seem to be much more susceptible to weight gain than before I started taking the medication. I typically fluctuate a lot.

1) How true is the perception that methimazole causes weight gain?
2) Aside from watching intake and stepping up exercise, is there anything else that can be done to prevent weight gain?

[Mark Lupo, M.D.]

The med does not cuase the gain, it's the correction of the artificially high metabolism caused by the hyperthyroidism.  Average gain is about 15-20 pounds no matter how hyper is treated -- many patients can avoid this with careful attention to calorie and exercise (once hyper is stable and approved by your doctor).

[Ima_Mess]

I took it for 3 months and gained 30 pounds.