Renal effects of bunazosin, a new alpha 1-adrenoceptor blocker, in patients with mild-to-moderate essential hypertension.

Renal effects of 4-week fixed maintenance doses of bunazosin three times daily (2.0 mg t.i.d., n = 8) and propranolol (40 mg t.i.d., n = 8) were evaluated in patients with mild-to-moderate essential hypertension [World Health Organization (WHO) stages I and II]. Both bunazosin and propranolol decreased blood pressure (BP) significantly (p less than 0.05), but the magnitude of reduction in diastolic BP (DBP) was greater with bunazosin (p less than 0.05) than with propranolol. Bunazosin produced a nonsignificant increase in renal blood flow (RBF) by 14%, a significant increase in glomerular filtration rate (GFR) 11% (p less than 0.05), and a decrease in total renal vascular resistance (TRR) by 15% (p less than 0.05), whereas propranolol caused no significant changes in these parameters. Urinary sodium excretion rate and the fractional excretion of sodium were unchanged by either of the drugs. The results of this short-term study suggest that bunazosin may be a drug that will increase RBF and GFR and decrease TRR with a concomitant hypotensive action in patients with mild-to-moderate essential hypertension. Whether these renal functional effects of the drug would benefit such patients must be determined in long-term studies.