Via practica 1/2011

Chronotherapy in the treatment of hypertension

Hypertension represents a severe medical and socioeconomic problem, because high blood pressure still remains an essential cause of death and cardiovascular morbidity worldwide. Adequate control of hypertension in Slovakia and also in the world is not satisfactory. There is still a notable group of patients who do not notice their disease, or if they do, are not treated. Resistant hypertension presents an especially serious problem, because blood pressure control in this group of patients is most problematic. A variability of blood pressure during 24 hours occurs, and there is a decline in nocturnal values about 10-20% compared to daytime. Absence of physiological nocturnal fall of blood pressure in hypertensive patients is associated with target organ damage and according the results of some trials, also with a higher cardiovascular mortality. Administration of antihypertensive drugs at bedtime could modify a pathological diurnal rhythm, and thus lead to a better blood pressure control. A positive effect of bedtime administration of antihypertensive drugs on the nocturnal fall of blood pressure has been documented in some important clinical trials. Available data has suggested that higher nocturnal decline of blood pressure in nodippers reached by a correct titration and dosage of antihypertensive treatment could improve prognosis. Results of available clinical trials which evaluate a prognostic significance of blood pressure are not in this consideration unified. However, there is still a lack of valid evidence that pharmacological correction of abnormal blood pressure variability is associated with a better prognosis, and thus emphasises the need for further interventional studies.

Keywords: resistant hypertension, dipping, nondipping, diurnal rhythm, ambulatory blood pressure monitoring, chronotherapy