The acute and chronic effects of indoramin on renal function, hemodynamics, and transport.

The acute and chronic renal effects of indoramin, an alpha 1-adrenoceptor antagonist, were investigated in six normotensive men (mean +/- SEM age, 36 +/- 3 years). Renal clearance studies were done during steady-state water diuresis before administration of indoramin (baseline), 3-4 h after a single 50-mg oral dose (acute study), and after 7 days of treatment with 25 mg twice daily (chronic study). After a single 50-mg oral dose, mean supine blood pressure decreased from 117/76 mm Hg at baseline to 109/74 mm Hg (NS), and glomerular filtration rate and renal blood flow were unchanged. There were small decreases (0.05 less than p less than 0.1) in the fractional excretion of sodium and potassium. After chronic administration (7 days) of indoramin, no significant changes in blood pressure, renal function, renal hemodynamics, or fluid and electrolyte excretion were observed. Mean body weight tended to decrease and fractional sodium excretion increased slightly (NS) after 7 days of indoramin. Plasma renin and aldosterone concentrations tended to increase (NS) after chronic indoramin administration. The results of this study indicate that acute and chronic administration of indoramin does not adversely affect renal function, renal hemodynamics, or fluid and electrolyte excretion in normotensive subjects.