Methimazole vs. Propylthiouracil for Hyperthyroidism

Both methimazole and propylthiouracil (PTU) are used to treat hyperthyroidism. To compare these drugs, Japanese researchers randomized 396 patients with Graves hyperthyroidism to receive 15 mg of methimazole once daily, 30 mg of methimazole daily (given as 15 mg twice daily), or 100 mg of PTU three times daily.

At each of three time points (4, 8, and 12 weeks), the proportion of patients with normalized free thyroxine (T₄) levels was higher in the 30-mg methimazole group than in the other two groups. The differences were of borderline statistical significance at 4 and 8 weeks but significant at 12 weeks (normal free T₄ achieved in 97%, 86%, and 78% of patients in the 30-mg methimazole, 15-mg methimazole, and PTU groups, respectively). In pat…