Adult: Initially, 20-60 mg daily as a single or divided dose, reduced gradually once euthyroidism is achieved. Maintenance: 5-15 mg daily for at least 1 yr or 18 mth. Child: 4-12 yr: Initially, 15 mg daily.
Absorption: Rapid from the GIT (oral); peak plasma concentrations after 1-2 hrs. Distribution: High concentrations in the thyroid gland; crosses the placenta; enters breast milk. Metabolism: Hepatic; converted to methimazole. Excretion: Urine (<12% unchanged drug); 3-6 hrs (elimination half-life).