In 2004-2005, the antihypertensive effects of telmisartan 80 mg versus valsartan 160 mg combined with hydrochlorothiazide 25 mg were assessed in a large placebo-controlled trial in patients with stages 1 and 2 hypertension and demonstrated that both agents were highly effective in lowering blood pressure (BP) compared with placebo and that telmisartan lowered BP significantly greater than valsartan. To confirm this finding according to Food and Drug Administration guidelines, we performed a second large trial using the same design in an entirely separate patient population. The trial was double-blind with a 4 : 4 : 1 randomization scheme to compare once daily telmisartan 80 mg plus hydrochlorothiazide 25 mg versus once daily valsartan 160 mg plus hydrochlorothiazide 25 mg versus once daily placebo on reductions in seated clinic BP in patients with stages 1 and 2 hypertension. The primary endpoints were the changes from baseline in seated diastolic and systolic BP at the end of the 8-week treatment period. Safety endpoints included adverse events, changes in laboratory parameters and pulse rate. In total, 1185 patients were randomized (of which 1181 were treated and included in the primary analysis: 528 in the telmisartan-hydrochlorothiazide group, 523 in the valsartan-hydrochlorothiazide group, and 130 in the placebo group), changes from baseline in BP following telmisartan-hydrochlorothiazide (-24.6/-18.2 mmHg) were significantly greater than both placebo (-4.1/-6.1 mmHg) and valsartan-hydrochlorothiazide (-22.5/-17.0 mmHg) (versus placebo, P<0.0001 for systolic and diastolic BP; versus valsartan-hydrochlorothiazide, P=0.017 for systolic BP and P=0.025 for diastolic BP). The total number of patients with at least one adverse event reported was similar among the three treatment groups (placebo, 42%, telmisartan-hydrochlorothiazide, 36%, and valsartan-hydrochlorothiazide, 37%). Thus, this large, second trial confirms that telmisartan-hydrochlorothiazide at doses of 80/25 mg lowered both systolic and diastolic BP to a greater extent than valsartan-hydrochlorothiazide at doses of 160/25 mg in stages 1-2 hypertension. Although these are not the highest doses of these agents at present, at the time that the studies were conducted, they were the maximally approved dosages. Both studies support the strategy of using angiotensin receptor blockers with a higher dose of a thazide diuretic (25 mg) for enhancing the control of hypertension.
