Drug Interactions With Methimazole
The following sections explain in detail the potentially negative interactions that can occur when methimazole is combined with any of the drugs listed above.
Beta blockers are often given to people with hyperthyroidism in order to control the heart rate and blood pressure. Because hyperthyroidism affects how the body handles beta blockers, your healthcare provider will probably need to lower the dosage of your beta blocker as your hyperthyroidism improves.
Because hyperthyroidism affects how the body handles digoxin, your healthcare provider may need to lower your digoxin dosage as your condition improves.
Sodium Iodide I 131
Methimazole may interfere with the effectiveness of sodium iodide I 131 (a radioactive iodine medication). It is usually recommended to stop taking methimazole for three to four days before treatment with sodium iodide I 131.
Because hyperthyroidism affects how the body handles theophylline, your healthcare provider may need to lower your theophylline dosage as your condition improves.
Methimazole and warfarin may interact unpredictably, and changes in thyroid hormone levels may also affect how the body responds to warfarin. Therefore, your healthcare provider should monitor you closely while you are taking methimazole (and after you stop taking it) and make any warfarin dosage adjustments as necessary.