Urodynamic effects of doxazosin in men with lower urinary tract symptoms and benign prostatic obstruction. Results from three double-blind placebo-controlled studies.

Objectives: Urodynamic investigations provide an objective, quantitative evaluation of urinary function in patients with benign prostatic obstruction (BPO). The effects of doxazosin, a selective alpha 1-adrenoceptor antagonist, on urodynamic measurements were investigated in three double-blind, placebo-controlled clinical studies of the treatment of BPO.

Methods: 302 normotensive and mildly hypertensive men with BPO were evaluated. Patients were randomized to receive doxazosin (1-4 mg o.d.) or placebo for 4-29 weeks.

Results: Doxazosin significantly improved free urinary flow rates compared with placebo. Urodynamic studies confirmed that doxazosin was effective in improving urinary flow, and also showed a reduction in detrusor pressure, resulting in decreased voiding time and increased voided volume. Analysis of pressure-flow data demonstrated a significant reduction in a measure of urethral resistance in doxazosin-treated patients.

Conclusion: These results indicate that doxazosin is an important treatment option for patients with troublesome lower urinary tract symptoms and BPO.