Serious pancytopenia from methotrexate treatment of psoriatic arthritis

Other abnormal laboratory data included an albumin of 2.2 g/dL, a blood urea nitrogen of 62 mg/dL, a creatine of 1.6 mg/dL, a C-reactive protein of 14.6 mg/dL, a slightly prolonged prothrombin time with an international normalized ratio of 1.22, and an activated partial thrombin time of 42.9 seconds. The occurrence of mucositis or GI inflammation process, in combination with the increased mean corpuscular volume values, may have been an early warning of possible MTX-related side effects such as bone marrow suppression.