Successful preoperative preparation for thyroidectomy in Graves' disease using lithium alone: report of two cases.

To elucidate the effect of lithium carbonate in the preoperative preparation of patients with Graves' disease, it was given without any other antithyroid medication to two patients as an alternative to thionamide, which had caused adverse effects. The initial dose of lithium carbonate was 600 mg/day, and the final doses were 1200 and 900 mg/day, while the periods of administration were 67 and 27 days, respectively. The highest serum concentrations of lithium during the administration period were 0.83 and 0.43 mEq/l, respectively. This preoperative preparation lowered serum thyroid hormone levels and clinical improvement. A subtotal thyroidectomy was performed uneventfully in both patients, after which the serum lithium levels decreased rapidly and the thyroid hormone levels increased only slightly for a few days. No adverse effects of lithium carbonate were observed. Thus, we conclude that the administration of lithium carbonate alone is an effective and safe method for the preoperative management of Graves' disease when conventional antithyroid drugs show adverse effects.