CloseClose
Find a Drug
Advanced Search

Professional

Cardura

Clinical Pharmacology
font size

Clinical Pharmacology

Cardura

Placebo

47 15.6 -2.3 41 9.7 +0.7

    Doxazosin mesylate

49 14.5 -4.9|| 41 9.8 +2.9||  Study 2 (Titration to fixed dose-14 weeks)†

    Placebo

37 20.7 -2.5 30 10.6 +0.1

    Doxazosin mesylate 4 mg

38 21.2 -5.0|| 32 9.8 +2.3||

    Doxazosin mesylate 8 mg

42 19.9 -4.2|| 36 10.5 +3.3||  Study 3 (Titration to fixed dose-12 weeks)

    Placebo

47 14.9 -4.7 44 9.9 +2.1

    Doxazosin mesylate 4 mg

46 16.6 -6.1|| 46 9.6 +2.6 a AUA questionnaire (range 0-30) in studies 1 and 3. Modified Boyarsky Questionnaire (range 7-39) in study 2. * Change is to endpoint. † Change is to fixed-dose efficacy phase, 22-26 hours post-dose for studies 1 and 3 and 2-6 hours post-dose for study 2. † Study in hypertensives with BPH. § 36 patients received a dose of 8 mg doxazosin mesylate. || p < 0.05 (0.01) compared to placebo mean change.


In one fixed dose study (study 2) doxazosin mesylate therapy (4-8 mg, once daily) resulted in a significant and sustained improvement in maximum urinary flow rate of 2.3-3.3 ml/sec (TABLE 1) compared to placebo (0.1 ml/sec). In this study, the only study in which weekly evaluations were made, significant improvement with doxazosin mesylate vs. placebo was seen after one week. The proportion of patients who responded with a maximum flow rate improvement of ³ 3 ml/sec was significantly larger with doxazosin mesylate (34-42%) than placebo (13-17%). A significantly greater improvement was also seen in average flow rate with doxazosin mesylate (1.6 ml/sec) than with placebo (0.2 ml/sec).

In BPH patients (N=450) treated for up to 2 years in open-label studies, doxazosin mesylate therapy resulted in significant improvement above baseline in urinary flow rates and BPH symptoms. The significant effects of doxazosin mesylate were maintained over the entire treatment period.

Although blockade of alpha1 adrenoceptors also lowers blood pressure in hypertensive patients with increased peripheral vascular resistance, doxazosin mesylate treatment of normotensive men with BPH did not result in a clinically significant blood pressure lowering effect (TABLE 2). The proportion of normotensive patients with a sitting systolic blood pressure less than 90 mmHg and/or diastolic blood pressure less than 60 mmHg at any time during treatment with doxazosin mesylate 1-8 mg once daily was 6.7% with doxazosin and not significantly different (statistically) from that with placebo (5%). The onset and time course of symptom relief and increased urinary flow from Study 1 are illustrated in Figure 1.

TABLE 2 Mean Changes in Blood Pressure from Baseline to the Mean of the Final Efficacy Phase in Normotensives (Diastolic BP <90 mmHg) in Two Double-Blind, Placebo-Controlled U.S. Studies with Doxazosin Mesylate 1-8 mg Once Daily
  Placebo (N=85) Doxazosin Mesylate (N=183)
  Baseline Change Baseline Change
 Sitting BP (mmHg)