Simultaneous treatment of toxic diffuse goiter with I-131 and antithyroid drugs: a prospective study.

We report a prospective study to avaluate the effect of antithyroid drugs containing the sulfhydryl radical on the outcome of I-131 (RAI) therapy. Twenty-four male patients withe toxic diffuse goiter were assigned randomly into tow treatment groups: Group A received RAI treatment while on antighyroid drugs after attainment of euthyroidism; Group B received no antithyroid drugs before, or when, RAI was given. Patients in each group received a dose of RAI calculated to deliver approximately 5000 rads per treatment. The incidence of hypothyroidism at 12 mo was 8% for Group A and 36% for Group B (p less than 0.01). During 12-102 mo of follow-up, no additional hypothyroidism was encountered in Group A. Two patients with significantly elevated TSH levels were found in Group B, one at 20 mo and one at 75 mo after RAI. The mean time to cure was 15.2 +/- 9.1 mo for Group A and 19.7 +/- 8.2 mo. for Group B (NS: p more than 0.45). The improved therapeutic outcome of patients in Group A suggests that further validation of the method in a larger patient population, including females, is warranted.