Effects of single doses of a 20 mg frusemide/2.5 mg amiloride combination, 20 mg frusemide and placebo on plasma and urine electrolytes in healthy men.

The effects of single doses of a combination of 20 mg frusemide and 2.5 mg amiloride, of 20 mg frusemide and of placebo on plasma and urinary electrolytes were assessed in healthy volunteers using a randomized, crossover study. The combination significantly (P less than 0.001) increased the urinary volume compared with frusemide alone or placebo. Mean total urinary sodium was also significantly (P less than 0.001) increased by frusemide/amiloride compared with both frusemide and placebo. Mean total potassium excretion was reduced significantly (P less than 0.01) by frusemide/amiloride but total magnesium excretion was not significantly affected. The effects of frusemide/amiloride on plasma sodium, magnesium and potassium were similar to those of placebo. It is concluded that frusemide/amiloride has a greater diuretic and natriuretic effect than frusemide alone and does not increase potassium loss.