title: Ambulatory blood pressure control with bedtime aspirin administration in subjects with prehypertension.
abstract: BACKGROUND
  Aspirin has been found to prevent angiotensin II-induced hypertension and to induce nitric oxide (NO) release from vascular endothelium. Low-dose aspirin has also been shown to reduce blood pressure (BP) when administered at bedtime, as opposed to upon awakening, in untreated hypertensive patients and high-risk pregnant women. Accordingly, we investigated the effects on ambulatory BP of aspirin administered at different times of the day in prehypertension.
  
  
  METHODS
  We studied 244 subjects with prehypertension, 43.0 +/- 13.0 years of age, randomly divided in three groups: nonpharmacological hygienic-dietary recommendations; the same recommendations and aspirin (100 mg/day) on awakening; or the same recommendations and aspirin at bedtime. BP was measured for 48 consecutive hours before and after 3 months of intervention.
  
  
  RESULTS
  Ambulatory BP was unchanged in subjects randomized to either nonpharmacological intervention or aspirin on awakening. A significant ambulatory BP reduction was, however, observed in the subjects who received aspirin at bedtime (decrease of 6/3 mm Hg in the 24-h mean of systolic (SBP)/diastolic BP (DBP), respectively; P < 0.001), without changes in heart rate (HR) from baseline. BP was homogeneously controlled along the 24 h after bedtime aspirin administration (6/4 mm Hg reduction in activity mean of SBP/DBP; 6/3 mm Hg reduction in sleep-time mean, respectively).
  
  
  CONCLUSIONS
  This prospective trial documents a significant effect on BP of low dose aspirin only when ingested at bedtime by prehypertensive subjects. The timed administration of low-dose aspirin could thus provide a valuable and cost-effective approach for BP control in subjects at elevated risk of developing hypertension.
authors.affiliation: Bioengineering and Chronobiology Laboratories, University of Vigo, Vigo, Spain. rhermida@uvigo.es
authors.forename: Ramón C
authors.initials: RC
authors.lastname: Hermida
authors.forename: Diana E
authors.initials: DE
authors.lastname: Ayala
authors.forename: Artemio
authors.initials: A
authors.lastname: Mojón
authors.forename: José R
authors.initials: JR
authors.lastname: Fernández
mesh_terms: D000328:Adult; D001241:Aspirin / Q000008:administration & dosage* / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002940:Circadian Rhythm / Q000502:physiology; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000627:therapeutic use*; D011446:Prospective Studies; D012890:Sleep / Q000502:physiology; D013997:Time Factors
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin