BACKGROUND: There has been longstanding controversy over the use of magnesium 
sulfate infusion in the medical management of aneurysmal subarachnoid hemorrhage 
(SAH). Several clinical trials evaluating the beneficial effects of magnesium on 
cerebral vasospasm and their poor outcome have been published. However, results 
from the majority of these studies have been inconclusive. This meta-analysis 
was performed to evaluate the effectiveness of magnesium on patient outcomes 
after aneurysmal SAH.
MATERIALS AND METHODS: PubMed and the Cochrane library were searched for 
controlled clinical trials assessing the efficacy of magnesium sulfate infusion 
after aneurysmal SAH. Eight studies consisting of 936 patients were included.
RESULTS: There was a decreased risk of poor outcome at 3-6 months after SAH in 
magnesium treatment groups when compared to placebo [0.78 (95% CI 0.66-0.93)]. 
Poor outcome was defined as severe disability, persistent vegetative state, or 
death, as measured by the Glasgow outcome scale (GOS), extended Glasgow outcome 
scale (GOSE) or modified Rankin scale (mRS). The risk of mortality after SAH was 
unaffected by magnesium treatment [RR 0.68 (95% CI 0.58-1.27)].
CONCLUSION: Magnesium sulfate infusion decreases risk of poor outcome after 
aneurysmal SAH. Current studies in the literature do not suggest a role for 
magnesium sulfate in mortality reduction after SAH.