Effects of the Angiotensin II Receptor Blockers Telmisartan Versus Valsartan on the Circadian Variation of Blood Pressure: Impact on the Early Morning Period

Background: Ambulatory blood pressure (BP) monitoring has shown that BP typically declines by 10% to 20% during sleep and increases fairly rapidly in the early morning period. Because the early morning period has been associated with both loss of hypertension control and increased rates of myocardial infarction and stroke, there has been interest in evaluating the effects of antihypertensive therapy at this particular time of the day. The purpose of this study was to assess the effects of a long half-life (telmisartan, 24 h) versus intermediate half-life (valsartan, 6 to 9 h) on early morning BP in two scenarios: after an active dose and after a missed dose of each agent.

Methods: The study was a double-blind, randomized trial that compared telmisartan (40 to 80 mg once daily) versus valsartan (80 to 160 mg once daily) on early morning BP in 490 patients with hypertension. Ambulatory BP recordings were performed at baseline after a placebo period and again after 6 and 8 weeks of double-blind therapy in a randomized cross-over design. The monitoring patients received either an active dose or a placebo dose (to mimic a "missed" dose). The primary study end point was reduction in the BP in the early morning period (last 6 h of the dosing period).

Results: After the active dose, telmisartan reduced the BP during the last 6 h of the dosing period by -11/-7.6 +/- 0.8/0.6 mm Hg compared to -8.7/-5.8 +/- 0.8/0.6 mm Hg on valsartan (P = .02 for systolic BP and.01 for diastolic BP). On the day of the missed dose, telmisartan reduced the early morning BP by -9.0/-6.3 +/- 0.7/0.6 mm Hg versus -7.4/-5.1 +/- 0.7/0.4 mm Hg on valsartan (P = .09 for systolic BP and.06 for diastolic BP). On the day of the missed dose, reductions in 24-h average BP for the two antihypertensive agents were -10.3/-6.9 mm Hg for telmisartan versus -8.7/-5.9 mm Hg for valsartan (P = .06 for systolic BP and.056 for diastolic BP).

Conclusions: On a day of active therapy, telmisartan lowered both systolic and diastolic BP to a greater extent than valsartan for the last 6 h of the dosing interval. On a day in which a dose was missed, there was a notable trend for greater BP reduction during the latter part of the dosing interval on telmisartan versus valsartan. These results demonstrate that telmisartan achieved a greater effect than valsartan on BP during the early morning period in patients with hypertension.