Magnesium Is Not Neuroprotective in Stroke

Ali S. Raja, MD, MBA, MPH, FACEP, Seemant Chaturvedi, MD reviewing Saver JL et al. N Engl J Med 2015 Feb 5.

Prehospital treatment with magnesium did not lead to improved 90-day disability outcomes in patients with stroke.

In animal models of stroke, magnesium sulfate has shown benefit when administered within 2 hours of symptom onset. Prior human studies demonstrating no benefit of magnesium did not achieve that early infusion benchmark (Lancet 2004; 363:439). In a randomized, placebo-controlled, multicenter trial, researchers evaluated whether beginning magnesium infusion in the prehospital setting would improve 90-day disability.

During an 8-year period, 1700 patients with suspected stroke (mean age, 69 years; 43% women) who could be treated within 2 hours of symptom onset were randomized to magnesium or placebo infusion. The assigned treatment was administered as a bolus infusion started by paramedics (4 g magnesium sulfate or placebo over 15 minutes), followed by maintenance infusion initiated in the emergency department (16 g magnesium sulfate or placebo over 24 hours). Final diagnoses were ischemic stroke in 73% of patients, hemorrhagic stroke in 23%, and stroke mimics in 4%. Median time from last-known normal time to the start of infusion was 45 minutes; 74% of patients were treated within 1 hour. At 90 days, there were no differences between the magnesium and control groups in mean scores on the modified Rankin scale (the primary outcome), mortality, adverse events, or five secondary neurologic outcomes.

Citation(s):

Saver JL et al. Prehospital use of magnesium sulfate as neuroprotection in acute stroke. N Engl J Med 2015 Feb 5; 372:528.