The review by Klein and colleagues [1] on the treatment of hyperthyroid disease was comprehensive and well balanced. However, several important issues were not fully covered. I concur that propylthiouracil is the preferred therapy in pregnant women, not only because of the low or nonexistent risk for teratogenicity but also because of the rare abnormality of aplasia cutis congenita that may be associated with the use of methimazole in pregnancy.

Two distinct antithyroid drug regimens are available. In the first, the dose of drug is titrated to keep the patient euthyroid; in the second, a fixed drug dose is used to block thyroid hormone production, and iatrogenic hypothyroidism is averted by thyroxine replacement (block-replace). The block-replace regimen is easier to use; involves fewer clinic visits to achieve euthyroidism; and, theoretically, because a larger total dose of methimazole is being given, greater immunosuppressive effects on thyroid receptor antibody levels may occur. When the block-replace regimen is used for 6 months, remission rates of 59% can be achieved at 1 year [2]. If symptoms do recur after this short course, definitive treatment with radioiodine or surgery can be offered sooner than when the standard titration regimens lasting 1 to 2 years are used.

Regarding their discussion of the treatment of thyroid-stimulating hormone-secreting pituitary adenomas, I agree that surgery is the cornerstone of therapy. However, adjunctive pituitary radiotherapy and the use of somatostatin analogs were not described. Many of these tumors tend to be large and invasive. In most cases, surgical removal is incomplete, and, even after pituitary irradiation, only about 40% of patients can be cured. In a review of 52 patients with thyroid-stimulating hormone-secreting adenomas, octreotide (a long-acting somatostatin analog) was found to reduce thyroid hormone levels in all patients, and these levels returned to normal in 77% of patients [3]. Partial tumor shrinkage was observed in one third of patients receiving long-term octreotide therapy. Octreotide is an effective treatment when surgery and radiotherapy have failed to cure the disease, and it requires further evaluation as a primary treatment for these tumors.