Clinical evaluation of effects of prazosin in patients with benign prostatic obstruction. A double-blind, multi-institutional, Paraprost-controlled study.

Prazosin, a selective alpha 1-adrenoceptor blocker, was compared with Paraprost in a double-blind, multi-institutional study in patients with benign prostatic hyperplasia. The trial encompassed 77 evaluable patients in the prazosin group and 79 in the Paraprost group. Both drugs significantly improved obstructive and irritative symptoms. Residual urine (volume or percentage of total urine) was reduced by both prazosin and Paraprost. Average and maximum flow rates increased significantly in the prazosin group while those were unchanged in the Paraprost group. Side effects occurred in 1 patient treated with prazosin (1.1%) and 3 patients with Paraprost (3.3%). Thus, we confirm the clinical value and minimal side effects of prazosin in the treatment of bladder outflow obstruction resulting from benign prostatic hyperplasia.