News - Hypertension Week of Jan. 25, 2004/ Vol. 3 No. 04

Study: Extended Melatonin Use Cuts Nighttime Blood Pressure in People With Hypertension

Patients with hypertension who undergo long-term treatment with melatonin have lower nighttime blood pressure, according to a study reported in the January 20 rapid access issue of Hypertension.

This finding suggests that melatonin, a naturally occurring hormone in the body, might be a beneficial addition to traditional high blood pressure treatments.

Lead author Frank Scheer, a neuroscientist at Brigham and Women's Hospital, said melatonin's effect on blood pressure might be due to its ability to help regulate the body's biological clock.

"It has been reported that people with high blood pressure often have suppressed nighttime melatonin levels," Scheer said. "We have recently found that people with high blood pressure have actual anatomical disturbances of their biological clocks. This finding might open the door for a new approach for treating hypertension."

The researchers evaluated the effect of melatonin after one dose and after a three-week treatment regimen in their study of 16 men. Patients taking repeated melatonin had lower nighttime systolic blood pressure by 6 mm Hg and diastolic blood pressure by 4 mm Hg. The single dose of melatonin had no effect on blood pressure. Patients taking melatonin also reported improved sleep, but Scheer said that effect was unrelated to blood pressure reduction in this study.

While this small study suggests the biological clock might be a mechanism involved in the blood pressure reduction, Scheer and colleagues also believe that improved sleep over a long time might help reduce blood pressure as well.

Dr. Dan Jones, a high blood pressure expert and an American Heart Association spokesperson, cautioned that larger studies are needed before it can recommend melatonin to fight high blood pressure.

"Patients with high blood pressure should consult their own health care provider for specific advice, but no one should begin melatonin therapy for blood pressure management for the time being," said Jones, who is dean of the University of Mississippi Medical Center School of Medicine.

Scheer agreed, noting that the study is just a start. "Large-scale studies need to be done, as well as studies of potential interactions between melatonin and traditional antihypertensive treatments," he added.

Other sources: American Heart Association