Cholestyramine Use for Rapid Reversion to Euthyroid States in Patients with Thyrotoxicosis

Cholestyramine (CS) is an ion exchange resin, which binds to iodothyronines and would lower serum thyroid hormone level. The use of CS added to conventional antithyroid drugs to control thyrotoxicosis has been applied since 1980's, and several studies indicate that using CS in combination with methimazole (MZ) produces a more rapid decline in serum thyroid hormones than with only MZ treatment. Our recent retrospective review of five patients taking high dose MZ and CS, compared to age-, gender-, initial free thyroxine (T4) level-, and MZ dose-matched 12 patients with MZ use only, showed more rapid decline of both free T4 and triiodothyronine levels without more adverse events. CS could be safely applicable short-term adjunctive therapy when first-line antithyroid medications are not enough to adequately control severe thyrotoxicosis or side effects of antithyroid drug would be of great concern.