RENAL HEMODYNAMIC-EFFECTS OF BUNAZOSIN RETARD AND PRAZOSIN IN MILD TOMODERATELY HYPERTENSIVE PATIENTS WITH NORMAL OR MODERATELY IMPAIRED RENAL-FUNCTION

Effective renal plasma flow (ERPF) and glomerular filtration rate (GFR ) were measured in 53 hypertensive patients (26 renally impaired, 27 w ith normal renal function) before and after treatment with sufficient bunazosin retard or prazosin to control their high blood pressure. Aft er a 3-week placebo run-in period, patients were classified as normal (creatinine clearance > 80 ml/min) or renally impaired (20-55 ml/min), and randomly assigned to bunazosin retard or prazosin. There followed a dose titration (T) phase of 6-7 weeks, and a maintenance (M) phase of 4 weeks. Blood pressure was satisfactorily controlled (sitting dias tolic pressure less-than-or-equal-to 90 mmHg or decreased by greater-t han-or-equal-to 10 mmHg) by both drugs in both groups. Bunazosin Retar d was associated with increases in GFR and ERPF in both normal and ren ally impaired groups; the increases were statistically significant in the renally impaired group (n = 14). Prazosin was associated with smal l decreases in both measures in both groups. One patient died of myoca rdial infarction during the placebo run-in. There were no other seriou s adverse events. Four patients reported dizziness (2 with each drug). We conclude that with appropriate dose titration, bunazosin retard is well tolerated and preserves renal blood flow when used to treat hype rtension in patients with renal insufficiency.