Methimazole has 8 known drug interactions based on U.S. FDA drug labeling data. 1 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Levothyroxine Sodium, Adrenergic Blockers, Digitalis Glycosides. Patients taking Methimazole should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 8
- Major
- 1
- Moderate
- 6
Major (1)
- Methimazole + Levothyroxine Sodium— May decrease thyroid hormone secretion, which may result in hypothyroidism when used with levothyroxine.
Moderate (6)
- Methimazole + Adrenergic Blockers— Hyperthyroidism increases clearance of beta blockers; dose reduction may be needed when hyperthyroid patient becomes eut…
- Methimazole + Digitalis Glycosides— Serum digitalis levels may increase when hyperthyroid patients become euthyroid; reduced digitalis dosage may be needed.
- Methimazole + Nonselective Beta-Adrenergic Antagonists— Hyperthyroidism increases clearance of beta blockers with high extraction ratio. Dose reduction may be needed when patie…
- Methimazole + Sodium Iodide I 131— Thionamide medication that interferes with accumulation of radioiodide by the thyroid. Discontinue 3 days before procedu…
- Methimazole + Theophylline— Theophylline clearance may decrease when hyperthyroid patients become euthyroid; dose reduction may be needed.
- Methimazole + Warfarin— Methimazole may inhibit vitamin K activity, increasing warfarin activity. Additional monitoring of PT/INR is recommended…