Angiotensin II receptor antagonist plus a thiazide diuretic is more efficacious for treating hypertension than either drug alone

Objectives: To identify a combination of telmisartan and hydrochlorothiazide (HCT) that provides antihypertensive efficacy superior to that afforded by the individual monotherapies, and to characterize the dose-response profiles for telmisartan 20-160 mg and HCT 6.25-25 mg alone and in combination. Safety parameters, including serum electrolytes, were also assessed. Methods: After a 4-week, single-blind, placebo run-in period, 818 patients aged 19-80 years with mild-to-moderate hypertension were allocated randomly to groups to receive 8 weeks of double-blind, once-daily treatment with placebo, telmisartan (20, 40, 80, or 160 mg), HCT (6.25, 12.5, or 25 mg) or one of 12 telmisartan-HCT combinations. Results: Telmisartan 80 mg + HCT 12.5 mg decreased mean supine systolic (SBP)/diastolic (DBP) trough blood pressures by 23.9/14.9 mmHg - a reduction 8.5/3.4 mmHg greater than that produced by telmisartan 80 mg and 17.0/7.6 mmHg greater than that produced by HCT 12.5 mg (P< 0.01). Telmisartan 40 mg + HCT 12.5 mg reduced mean supine SBP/DBP by 18.8/12.6 mmHg - an improvement of 6.6/1.9 mmHg over the reduction achieved with telmisartan 40 mg and of 11.9/5.3 mmHg over that achieved with HCT 12.5 mg (P< 0.01 for each comparison except that for the effect of telmisartan 40 mg on DBP). Response analyses confirmed the additive antihypertensive efficacy of telmisartan plus HCT. All regimens were well tolerated. Telmisartan tended to ameliorate HCT-induced serum potassium losses. Conclusions: Telmisartan 80 mg + HCT 12.5 mg is an effective and well-tolerated treatment for patients with mild-to-moderate hypertension, providing significantly greater reductions in supine trough SBP and DBP than can be achieved with the individual monotherapies.