my personal edition > hypertension > news


  E-Mail this DGReview to a colleague

DGReview

Nightime Melatonin Supplementation May Be Useful in the Treatment of Essential Hypertension

Supplemental melatonin, taken daily for 3 weeks at bedtime, decreases nocturnal blood pressure and improves sleep quality in men with essential hypertension, according to a randomised, double-blind, placebo-controlled, crossover trial.

The biological clock is responsible for adaptation to rest and activity through regulation of morning increases in cortisol, heart rate, and glucose, and evening increases in melatonin levels.

Studies have suggested that patients with high blood pressure have anatomical disturbances of their biological clocks and often have suppressed night-time melatonin levels. These effects may increase the risk of cardiovascular incidents in the early morning.

Frank A.J.L. Scheer, PhD, at the Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States, and colleagues evaluated whether repeated bedtime melatonin reduces ambulatory blood pressure in patients with essential hypertension. The study was conducted at the Netherlands Institute for Brain Research in Amsterdam.

The study included 16 men with mild to moderate untreated, uncomplicated, essential hypertension. Patients were initially randomised to receive either oral melatonin (2.5 mg/day) or placebo 1 hour before bedtime for 1 day. Patients were subsequently given melatonin or placebo for 3 weeks and then crossed-over to the opposite treatment arm for 3 additional weeks.

Nocturnal systolic and diastolic blood pressure decreased significantly after 3 weeks of bedtime melatonin therapy, without changing heart rate. Specifically, mean sleep systolic blood pressure decreased by 6 mm Hg and mean sleep diastolic blood pressure decreased by 4 mm Hg. Notably, melatonin did not affect daytime systolic and diastolic blood pressure as compared to placebo.

Moreover, a 15 to 25% enhancement of the day-night rhythm amplitude of systolic and diastolic blood pressure was observed with 3 weeks of melatonin therapy as compared with placebo.

Repeated melatonin significantly increased sleep efficiency from 80% to 85% and increased actual sleep time from 5.6 to 6.1 hours. Melatonin therapy also reduced sleep latency from 33 to 22 minutes.

One-day melatonin therapy had no effect on systolic and diastolic blood pressure while asleep or awake. Moreover, acute melatonin did not significantly influence sleep efficiency, actual sleep time, or sleep latency.

The authors conclude that "repeated, but not single, bedtime melatonin intake significantly reduced sleep blood pressure in male patients with untreated uncomplicated essential hypertension."

"Melatonin taken at night could thus be a gentle alternative or supplement to regular antihypertensive medication," they propose.

Hypertension 2004 Feb;43:2:192-7. Epub 2004 Jan 19. "Daily Nighttime Melatonin Reduces Blood Pressure in Male Patients With Essential Hypertension"

E-Mail this DGReview to a colleague

To print, use this version