The effect of magnesium sulphate infusion on circulating catecholamine levels in severe gestational proteinuric hypertension. A report of 8 cases.

The effect of magnesium sulphate (MgSO4) infusion on blood pressure and circulating venous catecholamine levels in 8 patients with severe gestational proteinuric hypertension is described. A significant fall in blood pressure was noted after MgSO4 infusion; the maximal fall in diastolic blood pressure correlated with the greatest rise in serum magnesium levels (P less than 0.04). No significant change was observed in mean venous plasma adrenaline or noradrenaline levels after MgSO4 infusion, although the mean dopamine concentration declined significantly. It is concluded that the decrease in systemic vascular resistance after MgSO4 infusion in gestational proteinuric hypertension is mediated predominantly by mechanisms other than a change in circulating catecholamine levels.