RESEARCH - Aspirin administered at bedtime, but not on awakening, has an effect on ambulatory blood pressure in hypertensive patients

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J Am Coll Cardiol. 2005 Sep 20;46(6):975-83.

Comment in:

J Am Coll Cardiol. 2005 Sep 20;46(6):984-5.

Aspirin administered at bedtime, but not on awakening, has an effect

on ambulatory blood pressure in hypertensive patients.

Hermida RC, Ayala DE, Calvo C, López JE.

Department of Bioengineering and Chronobiology Laboratories,

University of Vigo, Campus Universitario, Vigo, Spain.

OBJECTIVES: The purpose of this research was to investigate in

untreated hypertensive patients the effects on ambulatory blood

pressure (BP) of aspirin (ASA) administered at different times of the

day.

BACKGROUND: Previous studies have shown that ASA produces an

administration time-dependent inhibition of angiotensin II. Low-dose

ASA has also been shown to reduce BP when administered before bedtime,

as opposed to upon awakening, in normotensive and hypertensive

volunteers, and in pregnant women at high risk for preeclampsia.

METHODS: We studied 328 untreated patients with grade 1 hypertension,

44.0 +/- 12.6 years of age, randomly divided into three groups:

nonpharmacological hygienic-dietary recommendations, the same

recommendations and ASA (100 mg/day) on awakening, or the same

recommendations and ASA before bedtime. Blood pressure was measured

every 20 min during the day and every 30 min at night for 48

consecutive h before and after 3 months of intervention. RESULTS:

After three months of nonpharmacological intervention, there was a

small and nonsignificant reduction of BP (<0.2 mm Hg; p = 0.648).

Blood pressure was slightly elevated after aspirin on awakening

(2.6/1.6 mm Hg in the 24-h mean of systolic/diastolic BP; p = 0.002).

A significant BP reduction, however, was observed in the patients who

received aspirin before bedtime (6.8/4.6 mm Hg in systolic/diastolic

BP; p < 0.001).

CONCLUSIONS: This prospective trial documents a significant

administration time-dependent effect of low-dose ASA on BP in

untreated hypertensive patients. The timed administration of low-dose

ASA could provide a valuable approach, beyond the secondary prevention

of cardiovascular disease, in the added BP control of patients with

mild essential hypertension.

PMID: 16168278

http://www.ncbi.nlm.nih.gov/pubmed/16168278

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