title: Effects of propylthiouracil and relatively small doses of iodide on early phase treatment of hyperthyroidism.
abstract: In order to compare the acute effects of three methods of treatment in hyperthyroid patients with diffuse goitre, values of thyroxine (T4), triiodothyronine (T3) in serum, T3-resin uptake (T3-U), free thyroxine index (FT4I) and free triiodothyronine index (FT3I) were employed as thyroid function parameters. In iodide (I-) group given iodine (3 or 6 mg/day) as iodinated lecithine once daily, the parameters were reduced acutely within one week after the start of treatment, reaching a plateau during the next week. In contrast to the changes in I- group, the thyroid function was decreased gradually and consistently for two weeks in the propylthiouracil (PTU 300 mg/day) group. In PT1+I- (300 mg/PTU plus 3 or 6 mg/iodide/day) group, the parameters were reduced acutely and progressively for two weeks. These results indicate that PTU+I- therapy is much more effective than PTU or I- alone in early phase treatment of hyperthyroidism. Another new finding was that the thyroid function increased again during the later addition of PTU (300 mg/day) in the patients treated with I- (3 or 6 mg/day) for one or two weeks. The well-known escape phenomenon from iodide inhibition took place counteracted the effect of PTU. Since blocking of thyroidal secretion by I- is only transient while synthesis of T3 and T4 continues, leading to greater amount of hormone stored in the gland, the treatment of hyperthyroidism with I- alone is a risky procedure.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy*; D007454:Iodides / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010713:Phosphatidylcholines; D011441:Propylthiouracil / Q000008:administration & dosage / Q000627:therapeutic use*; D013960:Thyroid Function Tests; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D007454:Iodides; D010713:Phosphatidylcholines; D014284:Triiodothyronine; D011441:Propylthiouracil; D013974:Thyroxine