Alpha-adrenoceptor inhibitors in the treatment of benign prostatic hyperplasia.

Although benign prostatic hypertrophy is the most common cause of urinary tract symptoms in men, the cause is still unclear. Recently it has been suggested that treatment with alpha-adrenoceptor inhibitors may be helpful in this condition. Eighty patients with prostatic obstruction were entered into a double-blind parallel study of prazosin versus placebo. There were 25 withdrawals or exclusions, leaving 55 patients for analysis. Mean maximal flow rates increased significantly more in patients treated with prazosin than in patients treated with placebo (p less than 0.005), but there was no significant reduction in maximal voiding pressure. The mean number of voids, recorded on diary cards, was reduced from an initial 10.0/24 hours by 2.1 in the final week, a significantly greater reduction than in the placebo group (p less than 0.01). However, there were no statistically significant changes in the filling cystometrograms. When patients were classified as responders or nonresponders in terms of bladder filling, urine flow, bladder emptying, weekly average of voids/24 hours, and nocturia, the proportion of patients responding to prazosin was significantly greater in all categories except bladder filling and emptying. It was concluded that prazosin at a dose of 2 mg twice daily is a safe and effective treatment for prostatic obstruction and may be used in patients awaiting surgery and in those who are unfit for operation.