Comparison of indapamide and low-dose hydrochlorothiazide monotherapy in black patients with mild to moderate hypertension.

OBJECTIVES

To assess, using ambulatory blood pressure monitoring (ABPM), the antihypertensive efficacy of hydrochlorothiazide 12.5 mg and indapamide 2.5 mg given as a monotherapy over 3 months to black patients with mild to moderate essential hypertension.

DESIGN

Single-centre, prospective, randomised open pilot study in three phases: (i) 1-week drug-free washout period; (ii) 2-week placebo run-in phase; and (iii) 3-month prospective open-label active treatment period.

RESULTS

Forty-two black patients with mean daytime diastolic BP (DBP) > or = 90 mmHg and < or = 115 mmHg (mean age 57 +/- 11 years, 28 women/14 men) were enrolled into the study. Overall, a profound and sustained BP reduction was achieved with indapamide at 3 months (N = 20). The 24-hour BP decreased from 150 +/- 17/94 +/- 6 mmHg to 130 +/- 19/82 +/- 9 mmHg (P < 0.0001 for systolic BP (SBP) and DBP at 3 months versus baseline); the mean daytime BP decreased from 155 +/- 15/98 +/- 6 mmHg to 134 +/- 18/87 +/- 10 mmHg (P < 0.0001 for SBP and DBP at 3 months versus baseline). The overall control (mean daytime DBP < 90 mmHg) and response (decrease in daytime DBP > or = 10 mmHg) rates achieved with indapamide were 10/20 (50%) and 13/20 (65%), respectively. In contrast, monotherapy with hydrochlorothiazide resulted in more modest BP reduction and control and response rates at 3 months (N = 22). The 24-hour BP decreased from 147 +/- 14/94 +/- 7 mmHg to 139 +/- 19/88 +/- 2 mmHg (P < 0.05 for DBP at 3 months versus baseline, P = NS for SBP); the mean daytime BP decreased from 151 +/- 14/98 +/- 5 mmHg to 144 +/- 16/93 +/- 10 mmHg (P < 0.05 for DBP at 3 months versus baseline, P = NS for SBP). The corresponding control and response rates were 7/22 (32%) and 8/22 (36%). Both hydrocholorothiazide and indapamide caused significant hypokalaemia.

CONCLUSIONS

Monotherapy with indapamide is associated with greater BP reduction and control and response rates than monotherapy with low-dose hydrochlorothiazide and may be an appropriate choice of antihypertensive diuretic therapy in black South African patients with mild to moderate hypertension.