Severe Bone Marrow Suppression Associated with Use of Clopidogrel

A 60 year-old male presented with fever, malaise, and myalgias. The patient was admitted 3 weeks prior for acute coronary syndrome, underwent coronary stent placement, and was started on clopidogrel. He denied any chills, night sweats, chest or abdominal discomfort, or bleeding. He denied any history of alcohol, tobacco or illicit drug use and did not report any drug allergies. Three weeks prior to admission, at the start of clopidogrel therapy, complete blood count was within normal limits. On admit, white blood cell count (WBC) was 0.9 x 10^3/uL, hemoglobin (Hb) 10.9 g/dL, platelet count (PLT) 94,000/uL, absolute neutrophil count 0, and reticulocyte percentage 0.8%. Extensive workup for infectious and rheumatologic etiologies was ultimately negative. He then underwent bone marrow biopsy which revealed a hypocellular marrow, relative erythroid hyperplasia, and marked myeloid hypoplasia. Megakaryocytes were slightly increased in number. There was no evidence of malignancy. Clopidogrel was discontinued and he was supported with growth factor stimulating agents and empiric antibiotics. Blood counts recovered in 9 days and fevers subsided. On the day of discharge, WBC was 17.6, Hb 12.7, and PLT 121,000. He was discharged on prasugrel in lieu of clopidogrel and thereafter monitored closely. Six months later, blood counts returned to normal limits.