Diuretic drugs benefit patients with hypertension more with night-time dosing

Objectives: Night-time chronotherapy in antihypertensive drugs has been shown to produce better blood pressure control and protect from cardiovascular morbidity and mortality. To date, this has been proven for several drug classes excluding thiazides diuretics. Given the peculiar response of blood pressure to thiazides in black people we sought to determine whether night-time chronotherapy with thiazides produces better control as already shown with other drug classes.

Methods: A subanalysis of a larger chronotherapy study with antihypertensive drugs in Nigerian Africans was done. The subpopulation of those whose disease was controlled after 12 weeks of diuretic monotherapy was analysed. Those who received drugs in the morning and at night were compared along control lines and some cardiac indices.

Results: Both groups were similar on all scores at baseline. After 12 weeks of monotherapy patients who received drugs at night had significantly lower systolic and diastolic blood pressure though control was achieved with both morning and night-time dosing. Also the left ventricular posterior and septal walls regressed better as well as left ventricular mass in the night-time group.

Conclusion: Though equally effective in reducing blood pressure and cardiac indices related to hypertension, patients taking their drugs at night recorded better values. This makes diuretics equally amenable to night-time chronotherapy as other drug classes. This effect should be explored to reduce the morbidity and mortality consequences of hypertension.