A Randomized Trial of the Effect of an Angiotensin II Receptor Blocker SR47436 (Irbesartan) on 24-Hour Blood Pressure in Patients with Essential Hypertension

The aim of this placebo-controlled, double-blind randomized study was to evaluate the duration of the effect of once-daily administration of irbesartan in patients with essential hypertension. After a placebo run-in baseline period (of 2-4 weeks), 79 patients were randomized to either irbesartan (one 100 mg tablet per day) or placebo, for 6 weeks. The primary outcome was the reduction in the mean 24-h blood pressure (BP) as assessed by ambulatory BP monitoring under standardized conditions. Seventy-six patients completed the study protocol. In the irbesartan group, the average reductions in 24-h systolic and diastolic BPs were 5.8 and 3.4 mmHg, respectively (95% confidence interval: 3.2-8.4/1.6-5.1 mmHg), and in the placebo group, they were -1.7 and -0.5 mmHg, respectively (95% confidence interval: -4.3 to 1.0/-1.8 to 0.7 mmHg). There were statistically significant differences in the average reductions of 24-h BP (7.5/3.9 mmHg, p<0.001), daytime BP (8.6/4.0 mmHg, p<0.001) and nighttime BP (6.1/3.4 mmHg, p<0.05) as well as casual BP (9.0/5.0 mmHg, p<0.001). The trough/peak (T/P) ratios for the systolic and diastolic BPs were 0.84 and 0.78, respectively, in the irbesartan group. The incidence of adverse events was similar in both groups. The results showed that irbesartan administered 100 mg once daily was well tolerated in the treatment of essential hypertension and was effective in producing sustained 24-h BP control.