Large Doses of Propylthiouracil in the Treatment of Hyperthyroidism*

WITH the introduction of the new antithyroid agents for the treatment of hyperthyroidism, clinicians focused their attention on two main factors: first, the minimal dose required to effect a satisfactory clinical improvement and second, the incidence of undesirable side reactions. The originally suggested dose of propylthiouracil was 75 mg. daily (1), but it was quickly determined by clinical trial that for primary hyperthyroidism 200 to 400 mg. daily of propylthiouracil was required for a satisfactory response (2); and for adenomatous goiter with hyperthyroidism 300 to 500 mg. daily was necessary, the size of the dose depending upon the size of the goiter. A similar experience occurred with Tapazole, since the initially suggested dose of 12 mg. daily was found to be inadequate; the present dose is between 20 and 40 mg. daily. We have been satisfied over the years with this dosage schedule because our results have been satisfactory, even though the response of some patients, particularly those with adenomatous goiter with hyperthyroidism, has been slow.