Medical treatment of toxic goiter in an area of iodine deficiency

ABSTRACT

The response to methimazole [1-methyl 1-2-mercapto-inidazole [MMI]] therapy, 10mg twice daily in 15 patients and propylthiouracil [PTU] therapy, 100mg twice daily in 10 patients with diffuse toxic goiter was evaluated in an area of iodine deficiency [Tehran]. The mean free T [4] index [FT4I] decreased from 22.7 +/- 6.8 [ +/- SD] to 10.8 +/- 2.8 In MMI-treated, and from25.1 +/- 6.8to 13.2 +/- 2.1 in PTU-treated patients, two weeks after treatment. The FT4I further decreased to 6.8 +/- 4.3 and 8.5 +/- 2.1 after four weeks of MMI and PTU administration, respectively. The mean free T3 index [FT3I] was 415 +/- 90, 162 +/- 44 and 117 +/- 46 in MMI treated and 430 +/- 80, 210 +/- 45 and 140 +/- 53 in PTU treated patients before and two and four weeks after treatment, respectively. The mean FT4I and FT3I had decreased more in the MMI treated groups as compared to the PTU treated patients, two weeks after treatment. In patients treated with MMI or PTU, 11 of 25 [44%] had subnormal FT4I after four weeks of treatment, of whom one had increased serum TSH. These results indicate that treatment with less than the recommended doses of thionamide compounds causes a rapid decline of thyroid hormone indices in patients residing in Tehran. The dosage of thionamide compounds as well as the duration of therapy with the initial doses necessary to induce euthyroidism, should be evaluated in various parts of the world