Effect of Telmisartan/Hydrochlorothiazide Combination Versus Nifedipine GITS on Ambulatory Blood Pressure and Sympathetic Activation

Background This study compares the effects of telmisartan hydrochlorothiazide (HCTZ) combination versus nifedipine GITS on ambulatory blood pressure (BP) and sympathetic activity, in patients with mild-to-moderate hypertension. Methods One hundred twenty-four outpatients with sitting diastolic BP ≥95 mm Hg and <110 mm Hg were randomized to telmisartan 80 mg/HCTZ 12.5 mg daily (n = 62) or nifedipine GITS 60 mg daily (n = 62) for 12 weeks, according to a prospective, open-label, blind end point, parallel-group design. At the end of a 2-week washout period and after 12 weeks of active treatment, 24-h noninvasive ambulatory BP monitoring (ABPM) was performed, clinic BP and heart rate were measured, and plasma norepinephrine and cardiovascular responses to mental stress induced by the color word test were assessed. Results Both treatments reduced ambulatory and clinic BP. However, the drug combination had an antihypertensive efficacy significantly greater than nifedipine GITS, as shown by the 24-h (P< .001), daytime (P< .001), and night-time (P< .01) ambulatory BP monitoring values, as well as by the clinic BP at trough (P< .05).The trough-to-peak ratio was similar, but the smoothness index was significantly higher with the combination for both systolic and diastolic BP (P< .05). A significant increase in plasma norepinephrine levels in resting conditions was observed with nifedipine GITS (+20%) but not with telmisartan/HCTZ combination. The color word test produced a greater increase in plasma norepinephrine and heart rate values in the patients treated with nifedipine GITS than in those treated with the combination. Conclusions These results suggest that the telmisartan 80 mg/HCTZ 12.5 mg combination provided a more sustained and homogeneous BP control than nifedipine GITS 60 mg, without producing sympathetic activation.