Chronotherapy of arterial hypertension

Abstract

There are several reasons of using chronobiology principles in antihypertensive therapy. Firstly, influence of arterial blood pressure circadian rhythm disorders on the risk of cardiovascular and kidney complication of arterial hypertension and secondly, circadian rhytm of the above complications. Chronotherapy itself is a method of adjusting the concentration and power of the drug influence in time based on the circadian rhythms of biological phenomena, which are supposed to be influenced by the drug also during antihypertensive therapy. Usually the importance of two parameters of the arterial blood pressure circadian rhythm is being emphasized, as their abnormal values worsen the prognosis for patients with arterial hypertension. These parameters are: the value of nocturnal fall of blood pressure comparing to diurnal value and value of blood pressure morning rise. There are the following kinds of blood pressure pattern: 1. patients with abnormal nocturnal fall of blood pressure (< 10%), called nondippers; 2. patients whose pressure even increases in the night (< 0%), called risers or reverse dippers; 3. patients with a high nocturnal fall of blood pressure (> 20%), called extreme dippers. Abnormally increased rise of morning pressure is called morning surge. The longacting drugs administered in the morning are optimal for patients with normal circadian rhythm of blood pressure. For patients with abnormal nocturnal fall of blood pressure it seems that evening dosing of drugs which change the pressure pattern from nondipper to dipper is appropriate.
In many cases in order to control sudden morning pressure surges which increase the risk of cardiovascular incidents, morning administration of a longacting antihypertensive drug is effective. If it is not, then further therapy should be based on night pressure values. For nondipper patients evening dosing should secure the morning surge. For dipper patients one has to consider adding an evening dose of one of the longacting drugs. In order to control the morning surge of an extreme dipper patient (that is one with very low pressure values in the night) it is necessary to supplement longacting drugs being used with a small evening dose, or introducing α-adrenolitics. Current research progress gives hope that in the future we might also have chronotherapeutics available for such therapy.