Prophylaxis and treatment of magnesium depletion.

Magnesium deficiency may develop during diuretic treatment, causing serious cardiac arrhythmias hitherto ascribed to potassium depletion. Intravenous magnesium replacement therapy replenishes intracellular magnesium and potassium and inhibits cardiac arrhythmias which may occur during diuretic treatment; oral magnesium supplementation is also effective. The co-administration of amiloride with a distal-tubule diuretic prevents increased renal excretion of magnesium. Doses of diuretics should be restricted to the minimum compatible with the achievement of clinical objectives.