A prospective, randomized, open-label trial comparing telmisartan 80 mg with valsartan 80 mg in patients with mild to moderate hypertension using ambulatory blood pressure monitoring.

OBJECTIVE: To compare the antihypertensive efficacy and tolerability of telmisartan 80 mg with valsartan 80 mg throughout a 24 h dosing interval.

DESIGN: A prospective, randomized, open-label, blinded end point, parallel group study. Treatment efficacy was compared using ambulatory blood pressure monitoring (ABPM), cuff sphygmomanometry and calculated responder rates. Tolerability was assessed by physical examination, laboratory parameters, 12-lead electrocardiogram, blood pressure and heart rate monitoring, and evaluation of adverse events.

SETTING: Thirty-five centres in the United States.

PATIENTS: Four hundred and twenty-six patients with mild to moderate essential hypertension entered the study. Ninety-two per cent (n=393) completed the study.

INTERVENTIONS: Patients underwent a four-week, single-blind, placebo run-in period before being randomly assigned to once-daily oral telmisartan 80 mg (n=214) or valsartan 80 mg (n=212) for an eight-week, open-label treatment period.

RESULTS: Treatment with telmisartan was associated with a significantly greater mean reduction from baseline in the last 6 h ABPM mean for diastolic blood pressure compared with the valsartan-treated group (-7.5+/-0.6 mmHg versus -5.2+/-0.6 mmHg, respectively, P<0.01). Secondary analyses showed significantly greater efficacy with telmisartan 80 mg than with valsartan 80 mg, including greater mean reductions from baseline of ABPM (systolic blood pressure and diastolic blood pressure) during the daytime (06:00 to 21:59) and morning (06:00 to11:59) hours, and larger decreases in trough cuff blood pressure (P<0.01). Both treatments showed placebo-like tolerability profiles.

CONCLUSIONS: Telmisartan 80 mg once daily was superior to valsartan 80 mg once daily in reducing diastolic blood pressure during the last 6 h of the 24 h dosing interval. These results may be due to telmisartan's longer plasma half-life or to a higher potency compared with valsartan, such that a higher dose of valsartan may produce effects similar to those of 80 mg telmisartan. These data confirm the long duration of action of telmisartan with consistent and sustained control of blood pressure over 24 h and during the last 6 h of the dosing interval. Both treatments were well tolerated; the adverse event data confirmed the excellent tolerability profiles of telmisartan and valsartan that have been reported previously.