The effect of melatonin on circadian blood pressure in patients with type 2 diabetes and essential hypertension

INTRODUCTION: The aim of this study was to evaluate the effect of melatonin on blood pressure in patients with essential hypertension receiving medical treatment and with type 2 diabetes in good metabolic control. MATERIAL AND METHODS: The study lasted 8 weeks. Patients were equipped with a 24-hour ambulatory blood pressure monitor and took melatonin (3 mg a day in the evening) for 4 weeks. The patients were divided into four groups: group 1 (n = 32) including dippers, group 2 (n = 34) non-dippers treated with melatonin; and two control groups: group 3 (n = 28) including dippers and group 4 (n = 30) non-dippers treated without melatonin. After 4 weeks patients took melatonin for the next 4 weeks (5 mg a day). In each visit were analyzed: systolic, diastolic and mean blood pressure in both day and night time. RESULTS: We observed that 29.5% non-dippers (n = 10) treated with melatonin in a dose of 3 mg/day achieved features of dippers compared to control group (p < 0.05). Five mg of melatonin per day restored normal diurnal blood pressure rhythm in 32.4% non-dippers (n = 11, p < 0.05). In non-dippers treated with melatonin significant decreases of diastolic, systolic and mean night blood pressure values (p < 0.05) were observed. CONCLUSIONS: More than 30% of non-dippers with type 2 diabetes treated with melatonin were restored to the normal circadian rhythm of blood pressure. The effect of melatonin in both doses (3 mg and 5 mg) was significant for non-dippers only and included nocturnal systolic, diastolic and mean arterial pressure.