Effect of doxazosin on the symptoms of benign prostatic hyperplasia: results from three double-blind placebo-controlled studies.

The urinary symptoms characteristic of benign prostatic hyperplasia (BPH) can have a considerable impact on patients' quality of life. Symptom score assessment is now used in BPH, although a number of different instruments are available. Controlled clinical trials with selective alpha 1 adrenoceptor antagonists such as doxazosin, prazosin and terazosin have shown these agents to be effective in the treatment of BPH. The effects of doxazosin on the severity and bothersomeness of BPH symptoms were determined in three multicentre, double-blind, placebo-controlled clinical studies, involving a total of 609 normotensive and hypertensive patients. Doxazosin was initiated at a dosage of 0.5 or 1 mg once daily, with a final dose range of up to 12 mg once daily. The duration of active treatment was 12 to 14 weeks. Significant improvements were seen in symptom severity and bothersomeness with doxazosin compared with placebo, in both patient populations. The onset of symptomatic improvement was rapid, occurring within two weeks of treatment initiation, and efficacy was sustained throughout the treatment period. A long-term, open label extension of these studies has demonstrated sustained efficacy during 48 months of follow-up. Since symptom relief is the primary goal of therapy in BPH, and since doxazosin's effects are rapid in onset and sustained in duration, it appears that doxazosin is an effective agent for the treatment of symptomatic BPH in both normotensive and hypertensive men.