Nighttime administration of high-dose, sustained-release melatonin does not decrease nocturnal blood pressure in African-American patients: Results from a preliminary randomized, crossover trial

•Slow-release forms of melatonin have been reported to be effective at lowering nocturnal blood pressure.•In a controlled crossover we tested if 24 mg sustained-release melatonin administered nightly over 4-weeks reduced BP in 40 African-Americans.•Relative to studies in Euro-American or Middle Eastern patients, our data do not support use of melatonin as an antihypertensive agent. This preliminary study tested whether a high-dose, sustained-release form of melatonin reduced 24-hour blood pressure in African-Americans. Randomized, placebo-controlled, crossover pilot study of 40 self-defined African-American patients with essential hypertension. Urban, academic medical center and associated outpatient clinics. Patients ingested either melatonin (high dose [24 mg], sustained-release formulation] or placebo in randomized order over a 4-week period. Mean nighttime and daytime systolic and diastolic blood pressures, as measured with 24-hour ambulatory blood pressure monitors. The primary outcome was mean nighttime systolic blood pressure. There were no statistically differences between melatonin and placebo conditions in mean nighttime or daytime systolic or diastolic blood pressures. In contrast with studies in other populations, this preliminary study showed that nighttime dosing of continuous-release melatonin had no significant effect on nocturnal blood pressure in African Americans with essential hypertension when compared to placebo.