Alterations in Thyroid and Hepatic Function Tests Associated With Preparations of Sustained-Release Niacin

Abstract

Dr. Drinka reports two cases of decreased thyroid hormone binding capacity in persons taking slow-release niacin. In one patient, liver function abnormalities were also confirmed, a finding consistent with our case report. In the other patient, liver function tests were unavailable when the thyroid function abnormalities were first noted. The dose of niacin had been decreased before the repeated blood tests that showed normal results of liver function tests and a mildly decreased thyroxine-binding globulin level. This adjustment may have resolved liver function abnormalities and caused partial improvement in the thyroxine binding capacity. For this reason, we believe that hepatotoxicity cannot be excluded in this patient. Nonetheless, this report again emphasizes the need to interpret results of thyroid function tests cautiously in persons receiving niacin. Niacin therapy