Hypertension, But not "Prehypertension," Increases Stroke Risk -- and Should Combination Therapy Include a Calcium Antagonist?

March 16, 2004

In This Article

Amlodipine More Effective Than Valsartan at Controlling 24-Hour and Morning Blood Pressure

Monotherapy with the CCB amlodipine in hypertensive patients is more effective than the ARB valsartan at controlling blood pressure over 24 hours, including the morning blood pressure surge, according to a recent Japanese study. The results of this study are published in the February issue of the American Journal of Hypertension.[4] The same group of researchers at Jichi Medical School, Tochigi, reported last year that the morning surge in blood pressure is significantly associated with a risk of stroke in hypertensive patients.[5]

The effects of amlodipine vs valsartan were studied in 76 adults, mean age 65.6 years, with systolic blood pressure (SBP) ≥ 140 and < 180 mm Hg or diastolic blood pressure (DBP) ≥ 90 and < 110 mm Hg. Patients were randomized to treatment, which was open label. Both drugs were administered once daily, in the morning, amlodipine starting at 2.5 mg titrated to a maximum of 10 mg, and valsartan 40 mg titrated to a maximum 160 mg, for up to 18 weeks. Noninvasive ambulatory blood pressure monitoring (ABPM) was performed before and at the end of treatment.

Both drugs significantly reduced 24-hour SBP and DBP, but the antihypertensive effect of amlodipine was significantly greater than that of valsartan (clinical SBP, -26 vs 13 mm Hg, P = .001; 24-h SBP, -14 vs -7 mm Hg, P = .008). Although both drugs reduced lowest night SBP, only amlodipine also significantly reduced morning SBP, and amlodipine significantly reduced the morning SBP surge (morning SBP minus lowest night SBP) compared with valsartan (-6.1 vs +4.5 mm Hg, P = .02).

In trying to explain the reasons for their findings, which they say were unexpected, Kazuo Eguchi, MD, and colleagues suggest that ethnic differences between Japanese and white patients or higher salt intake among the Japanese population might account for the differences in the effects of the two drugs. They also speculate that the actual increase seen in the morning blood pressure surge with valsartan might be due to the relatively shorter half-life of valsartan compared with amlodipine. They note that other ARBs, such as telmisartan or irbesartan, which have a stronger antihypertensive effect than valsartan, might have different effects.

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