Fibrate-induced rhabdomyolysis with myoglobinemia and transient renal failure in a patient with myopathy due to hypothyroidism.

Administration of a lipid-lowering fibrate to a patient with unrecognized hypothyroidism was followed by severe rhabdomyolysis with transient renal failure due to high serum myoglobin levels. Full recovery occurred after discontinuation of the fibrate, despite a subtherapeutic dose of levothyroxine, suggesting that the rhabdomyolysis was drug-induced. Evidence of mild hypothyroidism-related myopathy was found. This case is additional evidence that fibrates can cause muscular toxicity and that thyroid function should be evaluated in patients with high serum cholesterol levels and suggestive clinical symptoms.