Rheographic indications for reduced cerebral vasoconstriction after oral magnesium medication in tetanic patients, a double-blind, placebo-controlled trial.

Volume and tonus oscillations of cerebral blood vessels are measurable with rheoencephalography. A lowered amplitude under resting conditions and an increased reactivity after hyperventilation (with pronounced and prolonged vasoconstriction) was found in tetanic patients, 360 mg Mg/day (as magnesium citrate tablets) was administered in 17 tetanic patients (A) and a placebo in 18 patients (B) in a double-blind, placebo-controlled trial. After 4 weeks the hyperventilation-induced vasoconstriction was reduced significantly within group A compared to group B.