Standard dose 131I therapy for toxic multinodular goiter in an endemic goiter region.

1. The effect of the standard 15 mCi dose of 131I on the thyroid function of 25 patients from an endemic goiter region with toxic multinodular goiter of different sizes was determined. 2. The patients were followed for 1 to 5 years and 7 months (mean: 2 years and 10 months). Eighteen patients were treated with the antithyroid drugs propylthiouracil or methimazole before 131I and seven only received 131I. 3. All but three patients achieved euthyroidism after a single dose of 131I. Two patients in the antithyroid treatment group became hypothyroid 2 months and 2 years after the isotope therapy, respectively. Pretreatment with antithyroid drugs did not significantly modify the effectiveness of 131I treatment. 4. This simplified dose regimen of 131I was effective in the treatment of hyperthyroidism caused by multinodular goiter in an endemic region, and the efficacy was independent of the size of the goiter.