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

Objectives: This preliminary study tested whether a high-dose, sustained-release form of melatonin reduced 24 hour blood pressure in African-Americans. Design: Randomized, placebo-controlled, crossover pilot study of 40 self-defined African-American patients with essential hypertension. Settings/location: Urban, academic medical center and associated outpatient clinics. Interventions: Patients ingested either melatonin (high dose [24 mg], sustained-release formulation] or placebo in randomized order over a 4-week period. Outcome measures: 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. Results: There were no statistically differences between melatonin and placebo conditions in mean nighttime or daytime systolic or diastolic blood pressures. Conclusions: 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.