OBJECTIVE: The prophylactic use of nimodipine in patients with aneurysmal 
subarachnoid hemorrhage reduces the risk of ischemic brain damage. However, its 
efficacy seems to be rather moderate. The question arises whether other types of 
calcium antagonists offer better protection. Magnesium, nature's physiological 
calcium antagonist, is neuroprotective in animal models, promotes dilatation of 
cerebral arteries, and has an established safety profile. The aim of the current 
pilot study is to evaluate the efficacy of magnesium versus nimodipine to 
prevent delayed ischemic deficits after aneurysmal subarachnoid hemorrhage.
METHODS: One hundred and thirteen patients with aneurysmal subarachnoid 
hemorrhage were enrolled in the study and were randomized to receive either 
magnesium sulfate (loading 10 mg/kg followed by 30 mg/kg daily) or nimodipine 
(48 mg/d) intravenously until at least postoperative Day 7. Primary outcome 
parameters were incidence of clinical vasospasm and infarction. Secondary 
outcome measures were the incidence of transcranial Doppler/angiographic 
vasospasm, the neuronal markers (neuron-specific enolase, S-100), and the 
patients' Glasgow Outcome Scale scores at discharge and after 1 year.
RESULTS: One hundred and four patients met the study requirements. In the 
magnesium group (n = 53), eight patients (15%) experienced clinical vasospasm 
and 20 (38%) experienced transcranial Doppler/angiographic vasospasm compared 
with 14 (27%) and 17 (33%) patients in the nimodipine group (n = 51). If 
clinical vasospasm occurred, 75% of the magnesium-treated versus 50% of the 
nimodipine-treated patients experienced cerebral infarction resulting in fatal 
outcome in 37 and 14%, respectively. Overall, the rate of infarction 
attributable to vasospasm was virtually the same (19 versus 22%). There was no 
difference in outcome between groups.
CONCLUSION: The efficacy of magnesium in preventing delayed ischemic 
neurological deficits in patients with aneurysmal subarachnoid hemorrhage seems 
to be comparable with that of nimodipine. The difference in their 
pharmacological properties makes studies on the combined administration of 
magnesium and nimodipine seem promising.