Send to:

Choose Destination
See comment in PubMed Commons below
Am J Hypertens. 2005 Dec;18(12 Pt 1):1614-8.

Prolonged melatonin administration decreases nocturnal blood pressure in women.

Author information

  • 1Department of Obstetrics Gynecology and Pediatrics, Policlinico di Modena, Modena, Italy.



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.


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.


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.


These data indicate that prolonged administration of melatonin may improve the day-night rhythm of BP, particularly in women with a blunted nocturnal decline.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk