OBJECTIVES: Magnesium sulfate (MgSO4) may be useful in preventing neurological 
injury after subarachnoid haemorrhage (SAH). In this randomized, double-blind 
study we evaluated the safety and efficacy of MgSO4 infusion to improve clinical 
outcome after aneurysmal SAH.
METHODS: With ethics committee approval and informed consents, 45 patients with 
SAH were randomly allocated to receive either MgSO4 80 mmol/day or saline 
infusion for 14 days. All patients also received intravenous nimodipine. 
Episodes of vasospasm were treated with hypertensive, hypervolemic therapy. 
Neurological status was assessed 3 months after haemorrhage using Barthel index 
and Glasgow outcome scale (GOS). Incidences of cardiac and pulmonary 
complications were also recorded. Data were compared between groups using 
Mann-Whitney or Fisher exact tests as appropriate. P < 0.05 was considered 
significant.
RESULTS: Patient characteristics, severity of SAH and surgical treatment did not 
differ between groups. Although the number of episodes was not reduced, MgSO4 
shortened the duration of vasospasm. Patients receiving MgSO4 tended to have 
fewer neurological deficits, better functional recovery and an improved score in 
GOS. However, none of these outcome variables reached statistical significance. 
The incidence of cardiac and pulmonary complications in the MgSO4 group (43%) 
was also similar to that in the saline group (59%), P = 0.14.
CONCLUSIONS: MgSO4 infusion after aneurysmal SAH is well tolerated and may be 
useful in producing better outcome. A larger study is required to confirm the 
neuroprotective effect of MgSO4.