Side effects of epoprostenol infusion include rash, headache, jaw pain, leg pain, diarrhea, nausea, catheter infections, chest pain, anxiety dizziness, bradycardia, dyspnea, abdominal pain, musculoskeletal pain, tachycardia, flu-like symptoms, and anxiety/nervousness. Thrombocytopenia is commonly seen in patients with PPH treated with PG12. Occasionally, a decrease in other blood cell lines occurs leading to anemia or pancytopenia. Splenomegaly and hypersplenism are observed at times. While thrombocytopenia has been attributed to the antiplatelet effects of prostacyclin, the pathophysiology of pancytopenia is poorly understood. There are no studies that address thrombocytopenia and other hemopoietic abnormalities in people with pulmonary hypertension receiving epoprostenol. The possibility of myelofibrosis causing these hematologic abnormalities has not been investigated.