Hormonal response to acute diuresis--a comparative study of furosemide and azosemide

We observed and compared the hormonal response to acute diuresis for 6 hours by orally administered furosemide 40 mg and azosemide 60 mg in normal male volunteers. The treatment resulted in significant urine volume increase with its peak during 1 to 2 and 2 to 3 hours after administration, and the 6-hour cumulative urine volume was 2488 +/- 163 ml in furosemide and 2930 +/- 109 ml in azosemide, respectively. The plasma noradrenalin concentration rose with the increase of urinary noradrenalin excretion, but plasma adrenalin remained unchanged in spite of its increased excretion. Serum aldosterone and plasma renin activity rose with resultant increase of urinary aldosterone excretion. Such a stimulation of the renin-angiotensin-aldosterone system was greater with azosemide than with furosemide. Plasma ADH and serum prolactin concentration was also increased. As compared with the furosemide responses, 1 to 2 hour delayed responses were observed in urinary adrenalin and noradrenalin, plasma renin activity, serum and urinary aldosterone, plasma ADH and serum prolactin. This was probably caused by delayed onset of the diuretic action in the case of azosemide. The findings suggested that the differences in the hormonal responses of the two drugs are mainly explained by the difference in their diuretic phase.