L-Glutamine Therapy for Sickle Cell Anemia

Inclusion Criteria: To be eligible to participate in the study, a patient must meet all of the following inclusion criteria: * Patient is at least 18 years of age. * Patient has been diagnosed with sickle cell anemia or sickle ß0-thalassemia (documented by hemoglobin electrophoresis). * Patient has had at least two episodes of painful crises within 12 months of the screening visit. * If the patient has been treated with an anti-sickling agent within three months of the screening visit, the therapy must have been continuous for at least three months with the intent to continue for the next 14 months. * Patient or the patient's legally authorized representative has given written informed consent. * If the patient is a female of child-bearing potential, she agrees to practice a recognized form of birth control during the course of the study. * Patient is able to perform exercise tolerance test Exclusion Criteria: If the patient meets any of the following criteria, the patient must not be enrolled: * Patient has a significant medical condition that required hospitalization (other than sickle painful crisis) within two months of the screening visit. * Patient has diabetes mellitus with untreated fasting blood sugar \>115 mg/dL. * Patient has prothrombin time International Normalized Ratio (INR) \> 2.0. * Patient has serum albumin \< 3.0 g/dl. * Patient has received any blood products within three weeks of the screening visit. * Patient has a history of uncontrolled liver disease or renal insufficiency. * Patient is pregnant or lactating. * Patient has been treated with an experimental anti-sickling medication/treatment (except hydroxyurea) within 30 days of the screening visit. * Patient has been treated with an experimental drug within 30 days of the screening visit. * There are factors that would, in the judgment of the investigator, make it difficult for the patient to comply with the requirements of the study.