Phenoxybenzamine reduces bladder outlet obstruction in benign prostatic hyperplasia. A urodynamic investigation.

Nine patients with bladder outlet obstruction attributable to benign prostatic hyperplasia were treated with 15 mg of phenoxybenzamine daily. Spontaneous urinary flow, water cystometry, simultaneous pressure-flow-EMG, and the urethral closure pressure profile were measured before and at the end of 4 weeks of treatment with phenoxybenzamine. A significant reduction in residual urine volume and a significant increase in the first sensation and bladder capacity were found. All voiding pressure parameters were significantly reduced and flow rates significantly increased. Urethral closure pressure decreased significantly.