Clopidogrel-induced Thrombotic Microangiopathy in a Patient with Hypocomplementemia.

Clopidogrel was administered to a 67-year-old Japanese man to prevent the recurrence of cerebral infarction. Twelve weeks later, he was admitted to our hospital with acute renal failure, hemolytic anemia and thrombocytopenia, and was diagnosed with clopidogrel-induced thrombotic microangiopathy. Clopidogrel was immediately discontinued and corticosteroid and plasma exchange therapy were administered simultaneously. Thereafter, the patient's condition gradually improved. The patient had a decreased serum complement C3 level. This suggests that the activated alternative pathway is related to thrombotic microangiopathy (TMA). TMA is a critical drug-associated adverse reaction that clinicians should always be vigilant about, because clopidogrel is widely prescribed.