Attenuation by spironolactone of the magnesiuric effect of acute frusemide administration in patients with liver cirrhosis and ascites.

The effect of spironolactone on renal magnesium excretion under both basal conditions and conditions of frusemide-induced diuresis was studied in 11 control subjects with normal hepatic and renal function and in 12 patients with liver cirrhosis and ascites. In the control group, oral administration of spironolactone (200 mg daily for 5 days) resulted in a significant decrease in the mean renal excretion of both magnesium and potassium. In the cirrhotic patients, spironolactone did not significantly change the mean renal excretion of magnesium or potassium, but it produced a significant reduction in the frusemide-induced increase in the renal excretion of both potassium and magnesium. The study suggests that spironolactone decreases magnesium excretion in normal subjects and antagonizes the magnesiuric effect of frusemide in patients with liver cirrhosis and secondary aldosteronism.