Clofibrate-induced myopathy in a patient with primary hypothyroidism.

Acute muscle pain with stiffness developed in a patient with latent hypothyroidism after administration of clofibrate. Serum creatine kinase (CK), aspartate aminotransferase, and lactate dehydrogenase were markedly elevated, but returned to normal one and a half months after the discontinuation of clofibrate. Clofibrate challenge (750 mg/day) for three days caused muscle pain and an elevation in serum CK. Hypothyroidism may be a predisposing factor in the development of clofibrate-induced myopathy.