Pancytopenia, including macrocytic anemia, associated with leflunomide in a rheumatoid arthritis patient

A female rheumatoid arthritis patient was admitted for productive cough and general fatigue that had gradually developed after leflunomide therapy. Side effects including severe hypoxia, thrombocytopenia, lymphocytopenia, and macrocytic anemia with schistocytes (probably drug-induced megaloblastic anemia) were noted. Leflunomide-eliminating cholestyramine therapy successfully treated all conditions excluding severe hypoxia, which occurred owing to deteriorating interstitial pneumonia and complicated bacterial pneumonia following antibiotic treatment. This is a rare case of leflunomide-associated multiple hematopoietic impairments.