Objectives: To compare the effects of doxazosin on blood pressure when used for the treatment of benign prostatic hyperplasia (BPH) in men who are either physiologically or pharmacologically normotensive.
Methods: Sixty-three men with BPH were enrolled in two open-label, parallel, randomized studies. Thirty-one were physiologically normotensive and 32 had hypertension controlled by antihypertensive therapy (pharmacologically normotensive). Of these, 17 were taking calcium channel blockers; 6, angiotensin-converting enzyme inhibitors; and 9, beta blockers. After a 3-week titration period, patients from one study received doxazosin (4 mg/day) for 3 months, given as a single dose in either the morning or evening, and in the second study patients were randomized to receive either 4 mg or 8 mg daily, either in the morning or evening. Effects on blood pressure, maximum uroflow, and the Boyarsky symptom score were measured.
Results: Doxazosin produced statistically significant but clinically unimportant reductions in blood pressure in both physiologically and pharmacologically normotensive groups. Statistically and clinically significant improvements in BPH symptoms and maximal perfusion occurred in both groups within 1 month, and further improvements were improved after 3 months. These effects were evident whether doxazosin was administered in the morning or evening. Doxazosin was well tolerated, the only adverse events being dizziness in 5 patients and fatigue in 4. By protocol, all patients reporting adverse events were required to be discontinued from the study. Adverse events did not differ between the groups. There was some indication that patients experiencing adverse events also experienced greater reductions in blood pressure.
Conclusions: Doxazosin may be introduced for the treatment of BPH in hypertensive men whose blood pressure is already controlled by another antihypertensive agent, without a further clinical reduction in blood pressure. It is effective and well tolerated as a once-daily dose given in the morning or evening.