Effects of prazosin HCl on micturition disturbance associated with benign prostatic hypertrophy and bladder neck contracture.

The effects of alpha 1-adrenergic blockade with prazosin HCl were examined in 28 patients with benign prostatic hypertrophy and bladder neck contracture. The patients received 2-3 mg of prazosin HCl daily administered orally. Improvement in subjective symptoms was observed in 75% of the patients. We evaluated clinical effects as the minimum time of micturition (calculated as the ratio of voided volume/maximum flow rate) for voided volumes less than 200 ml and the maximum flow rates and average flow rates for voided volumes over 200 ml. Evaluation of the findings on a flow rate nomogram revealed improvement in maximum flow rates and average flow rates in 41% of the patients. Side effects such as dizziness developed in only 1 patient.