Effects of prazosin HCl on the urethral pressure profile in patients with benign prostatic hyperplasia.

The effects of prazosin HCl on the urethral pressure profile (UPP) were studied in 14 patients with benign prostatic hyperplasia. Urethral pressure profilometry was performed 1 h after oral administration of 1 or 2 mg prazosin HCl. Functional profile and continence zone lengths were significantly reduced following administration of 1 or 2 mg prazosin HCl, as compared with the pretreatment lengths. The administration of 2 mg prazosin HCl resulted in a significant decrease in prostatic peak pressure, whereas the maximum urethral closure pressure exhibited an insignificant decrease. The results suggest that the effects of prazosin HCl on UPP were dose dependent within the range from 1 to 2 mg.