Delayed Recognition of Levetiracetam-induced Pancytopenia.

Blood dyscrasias associated with levetiracetam use can be difficult to identify, especially when other potential differential diagnoses are concurrently present. Here we present a 57-year-old man with metastatic adenocarcinoma of unknown primary origin on levetiracetam who initially presented with an in-stent thrombosis of the right external iliac vein and then developed worsening thrombocytopenia followed by pancytopenia. Levetiracetam was not identified as the culprit until other causes like platelet consumption, heparin-induced thrombocytopenia, idiopathic immune thrombocytopenic purpura, and bone marrow involvement by metastatic disease were ruled out. LEARNING POINTS: Levetiracetam can cause both acute and delayed-onset pancytopenia through bone marrow suppression.The phenomenon is normally reversible and blood counts improve with drug cessation.Clinicians should consider checking a complete blood profile within a month of drug initiation, particularly in high-risk patients. © EFIM 2021.