The purpose of this study is to determine the safety and efficacy of intravenous magnesium in shortening the duration of a pain crisis and to determine the health-related quality of life and short term outcomes of children treated with intravenous magnesium during an acute pain crisis.

It is well known that children with sickle cell disease are at risk for acute pain crises. The usual treatment for these pain crises, intravenous fluids and pain medicines such as morphine, has changed little over the past three decades. In a pilot study, the addition of intravenous magnesium to standard therapy decreased length of stay; however, this study was not randomized, not blinded, not placebo-controlled, and not adequately powered to assess safety.

We will conduct a multi-center, randomized, double-blind, placebo controlled trial of about 208 children, ages 4-21 years. Patients will be randomized to receive intravenous magnesium sulfate or placebo every 8 hours for a total of 6 doses, or until discharge. Patients will return for a routine clinic visit up to 3 months after discharge for a baseline assessment. Patients will also complete health-related quality of life measures at 4 timepoints throughout the study.

Inclusion Criteria:

• age 4-21 years, inclusive
• Sickle cell anemia (Hb SS) or Sickle beta zero thalassemia disease (Hb Sβ°)
• failed intravenous opioid pain management in the emergency department prior to the decision to admit the patient
• admitted to the inpatient unit for sickle cell pain crisis

Exclusion Criteria:

• patient received more than 12 hours of intravenous pain medication prior to enrollment
• previous enrollment in this study (only one admission per child is eligible)
• history of allergy/intolerance to both intravenous morphine and hydromorphone
• known other cause for pain (avascular necrosis, gall bladder disease, priapism, etc.)
• patient with greater than 10 admissions for pain crisis in the past year
• patient maintained on daily opioids or chronic transfusions for chronic sickle cell pain
• transfusion within the previous two months
• known kidney or liver failure (elevation of liver function tests does not warrant exclusion)
• known pulmonary hypertension
• pregnancy
• diagnosis of bacterial infection, fever ≥39.5°C, acute chest syndrome, hemodynamic instability or sepsis
• current oral magnesium supplementation or current enrollment in another therapeutic study protocol
• previously diagnosed clinical stroke
• current or planned use of neuromuscular blocker, nifedipine, ritodrine, or terbutaline
• allergy to magnesium sulfate
• discharge from an inpatient unit within 72 hours of arrival in the emergency department for the current pain crisis

Participant Flow and Baseline characteristics are reported for all randomized patients; however, adverse events only include the 204 (98%) who received study drug.