Clinical comparison of selective and non-selective alpha(1A)-adrenoceptor antagonists for bladder outlet obstruction associated with benign prostatichyperplasia: Studies on tamsulosin and terazosin in Chinese patients

To examine the clinical usefulness of selective and nonselective alpha(1)-a drenoceptor antagonists, we compared a selective (tamsulosin) and non-selec tive (terazosin) alpha(1)-adrenoceptor antagonists in the treatment of Chin ese patients with benign prostatic hyperplasia (BPH). The study was a singl e-blind, randomized, multicenter design to compare a fixed dose of tamsulos in (0.2 mg) or terazosin (2 mg) given once daily after breakfast for four w eeks. A total of 212 patients were enrolled with 201 patients included in t he analysis. The primary variables assessed were changes in total Internati onal Prostatic Symptom Score (IPSS), maximum urinary flow rate (Q(max)) and average urinary flow rate (AFR) four weeks after dosing. Adverse events we re recorded through the treatment period. Both tamsulosin and terazosin pro duced significant improvements in total IPSS (total score of 11.8 +/- 4.5; decrease in 45.1% and total score of 13.3 +/- 5.3; decrease in 39.0%, respe ctively) (p< 0.001), Q(max) (13.2 +/- 4.1 mL/s, 37.5% increase and 13.6 +/- 3.6 mL/s, 30.8% increase, respectively) (p <0.001) and AFR (7.7 +/- 3.3 mL /s, 37.5% increase and 7.8 +/- 3.1 mL/s, 25.8% increase, respectively) (p < 0.001) at endpoint. Tamsulosin was superior to terazosin in improvement of total IPSS (p <0.05) and AFR (p <0.05). The incidence of adverse events by administration of tamsulosin was less than that by terazosin (13 and 50, re spectively; p <0.01). Among the adverse event, incidence of dizziness (p <0 .001) and hypotension (p <0.01) by administration of terazosin were signifi cantly greater than that by tamsulosin. Both systolic and diastolic blood p ressure of sitting position decreased significantly in patients treated wit h terazosin (p <0.01). These results suggest that tamsulosin, a selective alpha(1A)- adrenoceptor antagonist, was superior to terazosin, a non-selective alpha(1)- adrenocept or antagonist, in efficacy and adverse events in patients with symptomatic BPH.