Urodynamic effects of alpha1-blocker tamsulosin on voiding dysfunction in patients with neurogenic bladder.

Background: The therapeutic role of alpha-blockers in the treatment of voiding disorders due to benign prostatic hyperplasia has been extensively examined. To investigate a possible effect of alpha1-blocker on urodynamic voiding parameters in patients with neurogenic bladder, we conducted a clinical trial using tamsulosin.
Methods: Twenty-four patients (14 men and 10 women) ranging from 24 to 82 years of age (mean age 61 years) with neurogenic bladder were analyzed. Urodynamic studies were performed before and after treatment with 0.4 mg tamsulosin daily for 4 weeks.
Results: On uroflowmetry, the average flow rate (from 4.6 +/- 3.3 to 6.7 +/- 3.0 mL/s, P = 0.04), maximum flow rate (from 9.4 +/- 6.8 to 14.1 +/- 7.0 mL/s, P = 0.016) and residual urine rate (from 46 +/- 29 to 32 +/- 21%, P = 0.02) improved significantly. In patients with detrusor contraction during voiding, detrusor opening pressure and detrusor pressure at maximum flow decreased significantly from 69.0 +/- 36.2 to 49.2 +/- 26.4 cmH2O (P = 0.046) and from 66.7 +/- 34.6 to 53.6 +/- 26.5 cmH2O (P = 0.007), respectively. On the other hand, in patients with detrusor areflexia, vesical opening pressure (from 78.2 +/- 23.4 to 61.6 +/- 25.2 cmH2O), or vesical pressure at maximum flow (from 68.6 +/- 23.2 to 62.9 +/- 25.2 cmH2O) did not change significantly after treatment.
Conclusion: Tamsulosin reduces functional urethral resistance during voiding and improves flow rate in patients with neurogenic bladder. It has more beneficial urodynamic effects in patients with detrusor contraction during voiding than in patients with detrusor areflexia.