A double-blind placebo-controlled study evaluating the onset of action of doxazosin gastrointestinal therapeutic system in the treatment of benign prostatic hyperplasia

Objective: To determine the onset of improvement in benign prostatic hyperplasia symptoms in patients after treatment with doxazosin gastrointestinal therapeutic system (DOX GITS) versus placebo. Methods: In this prospective, randomized, double-blind, placebo-controlled trial, baseline values, including International Prostate Symptom Score (IPSS) and maximum urine flow rate (Q _max), were determined following a 2-week placebo run-in. Patients received DOX GITS 4 mg/d (n = 108) or placebo (n = 105) for 14 days. IPSS was measured on Days 3, 7, and 14; Q_max on Days 1, 3, 7, and 14; and the patients' perception of improvement was measured on Days 1 and 2 in the evening at home and in the office on Day 14. Results: Significantly more patients treated with DOX GITS than placebo perceived improvement after Day 1 (60.6% vs. 41.9%) through Day 14 (84.3% vs. 64.1%). On Day 1, improvement in Q _max with DOX GITS was not significantly different compared with placebo. On Day 3 of the trial (1) IPSS improvement was significantly greater with DOX GITS than with placebo; (2) proportion of patients with ≥30% improvement in IPSS was significantly greater with DOX GITS (49.5%) than placebo (28.4%) and remained so through Day 14; (3) improvement in Q_max was significantly greater with DOX GITS (3.7 mL/s) than placebo (1.9 mL/s) and remained so through Day 14; (4) proportion of patients with ≥3 mL/s increase in Q_max was statistically greater with DOX GITS (54.4%) versus placebo (30.8%) and remained so through Day 14. Conclusions: DOX GITS significantly improved IPSS and Q_max by Day 3 of treatment, and these changes were maintained through Day 14. More patients receiving DOX GITS than placebo perceived improvement in symptoms as early as Day 1.