The addition of doxazosin to the therapeutic regimen of hypertensive patients inadequately controlled with other antihypertensive medications: a randomized, placebo-controlled study

This randomized, double-blind, placebo-controlled study evaluated the use of doxazosin as an add-on therapy for inadequately controlled hypertension. Patients with a sitting diastolic blood pressure (BP) of 95 to 115 mm Hg received either doxazosin (n = 38) or placebo (n = 32) in addition to one or two baseline antihypertensive medications. After an upward titration period, patients were maintained on a fixed dosage of doxazosin (1 to 16 mg/day) or matching placebo for 4 weeks. Doxazosin add-on therapy led to improvements, compared with placebo, in sitting systolic BP (adjusted mean change = −20.9 v −8.5 mm Hg, P = .001), sitting diastolic BP (−13.0 v −8.1 mm Hg, P = .026), and standing systolic BP (−22.0 v −11.5 mm Hg, P = .011). Baseline antihypertensive therapy was gradually tapered or discontinued in patients who achieved a target reduction in BP (sitting diastolic BP of < 90 mm Hg in addition to a minimum improvement of 10 mm Hg in sitting diastolic BP over baseline) with add-on therapy (55% [n = 21] with doxazosin, 31% [n = 10] with placebo). Twelve patients in the doxazosin group maintained the target reduction in BP after complete withdrawal of their baseline antihypertensive therapy, compared with none in the placebo group. A small but statistically significant positive effect on the lipid profile was seen in the doxazosin group during add-on therapy. Doxazosin treatment was well tolerated, with an adverse event profile similar to that of placebo. These findings demonstrate that doxazosin add-on therapy is an effective, well-tolerated treatment strategy for patients with inadequately controlled hypertension.