gms | German Medical Science

Objective: Being an N-methyl-D-aspartate (NMDA) receptor antagonist magnesium has been studied for its neuroprotective and vasodilatative feature in acute and delayed brain ischemia due to vasospasm in aneurysmal subarachnoid hemorrhage and stoke. A number of clinical phase II and III studies have correlated serum magnesium concentrations after intravenous continuous application to clinical outcome. However, no study supported its conclusion by providing evidence for a local increase in magnesium, i.e. in the cerebrospinal fluid (CSF) and the brain parenchyma. The objective of this observation was to correlate serum magnesium to CSF and brain microdialysis samples (MDS).

Methods: Twenty-five patients with a aneurysmal subarachnoid hemorrhage World Federation of Neurosurgeons (WFNS) grade IV and V were included. According to standard clinical treatment protocols all patients received a ventricular catheter, a frontal intracerebral microdialysis probe, and a continuous intravenous application of 80 mmol MgSO₄ per 24 hours. Magnesium concentrations of serum, CSF and MDS were recorded for a maximum of 14 days.

Results: We established a correlation of increase of serum magnesium by intravenous application to CSF and MDS magnesium. The continuous intravenous dosage of 80 mmol MgSO₄ per day is sufficient to double the CSF and MDS concentration of magnesium.

Conclusions: These pharmacokinetic findings serve as a basis for future preclinical and clinical investigations carried out to identify the therapeutic role of intravenous magnesium application in preventing acute or delayed brain ischemia in SAH and stroke.