title: Prolonged melatonin administration decreases nocturnal blood pressure in women.
abstract: BACKGROUND
  The nocturnal decline of blood pressure (BP) is almost coincident with the elevation of melatonin, which may exert vasodilatating and hypotensive effects. In this study we investigated whether prolonged nocturnal administration of melatonin could influence the daily rhythm of BP in women.
  
  
  METHODS
  In a randomized double-blind study, 18 women, 47 to 63 years of age and with normal BP (N = 9) or treated essential hypertension (N = 9), received a 3-week course of a slow-release melatonin pill (3 mg) or placebo 1 h before going to bed. They were then crossed over to the other treatment for another 3 weeks. In each woman ambulatory BP was recorded for 41 h at baseline at the end of each treatment period.
  
  
  RESULTS
  In comparison with placebo, melatonin administration did not influence diurnal BP but did significantly decrease nocturnal systolic (-3.77 +/- 1.7 mm Hg, P = .0423), diastolic (-3.63 +/- 1.3 mm Hg, P = .0153), and mean (-3.71 +/- 1.3 mm Hg, P = .013) BP without modifying heart rate. The effect was inversely related to the day-night difference in BP.
  
  
  CONCLUSIONS
  These data indicate that prolonged administration of melatonin may improve the day-night rhythm of BP, particularly in women with a blunted nocturnal decline.
authors.affiliation: Department of Obstetrics Gynecology and Pediatrics, Policlinico di Modena, Modena, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Cagnacci
authors.forename: Marianna
authors.initials: M
authors.lastname: Cannoletta
authors.forename: Antonietta
authors.initials: A
authors.lastname: Renzi
authors.forename: Francesco
authors.initials: F
authors.lastname: Baldassari
authors.forename: Serenella
authors.initials: S
authors.lastname: Arangino
authors.forename: Annibale
authors.initials: A
authors.lastname: Volpe
mesh_terms: D000284:Administration, Oral; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D002940:Circadian Rhythm; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008550:Melatonin / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D003692:Delayed-Action Preparations; D008550:Melatonin