Arginine Therapy for the Treatment of Pain in Children With Sickle Cell Disease

Inclusion Criteria: * Established diagnosis of sickle cell disease--Hemoglobin SS (Hb-SS) or Sβᴼ-thalassemia * 7-21 years of age * Weight \>= 25kg (55lbs) * Pain requiring medical care in an acute care setting (emergency department (ED), hospital ward, day hospital, clinic) requiring parenteral opioids, not attributable to non-sickle cell causes. Exclusion Criteria: * Decision to discharge home from acute care setting. * Diagnosis of sickle cell disease with any of the following types: hemoglobin SC disease (HbSC), hemoglobin beta thalassemia (Hb-Beta Thal), hemoglobin SD disease (HbSD), hemoglobin SE disease (HbSE), hemoglobin SO disease (HbSO), hemoglobin AS carrier (Hb AS) * Hemoglobin less than 5 gm/dL * Immediate Red cell transfusion anticipated * Renal dysfunction: Creatinine \>1.0 or 2 x baseline * Mental status or neurological changes * Acute stroke or clinical concern for stroke * Pregnancy * Allergy to arginine * Previous hospitalization \< 7 days * Use of inhaled nitric oxide, sildenafil or arginine within the last 14 days * Not an appropriate candidate in the investigator's judgement