Metabolism of the diuretic bumetanide in healthy subjects and patients with renal impairment.

The pharmacokinetics and metabolism of orally administered bumetanide were studied in five healthy subjects and in five patients with renal insufficiency. Healthy subjects excreted 51% of the dose as unchanged drug in the urine, whilst the patients with renal insufficiency excreted only 11% of the dose as bumetanide. Similarly the urinary excretion of the gamma-hydroxybutyl metabolite was reduced from 6% in healthy subjects to 2.3% in patients with renal impairment. In both groups of subjects the mean elimination half-life of the metabolite was greater than for bumetanide. The results indicate a possible accumulation of bumetanide and metabolite in patient with renal failure.