Antihypertensive drug treatment and circadian blood pressure rhythm: a review of the role of chronotherapy in hypertension.

Elevated nighttime blood pressure (BP) and a reduced day-night BP fall ("nondipping" condition) are strong predictors of cardiovascular complications, both in hypertension and in the general population. A reduced or inverted nocturnal BP fall might also be theoretically used to define the most appropriate timing for drug administration. In a systematic review of the available evidence, we show that bedtime dosing of antihypertensive medication reduces nocturnal BP and increases day-night BP fall more than standard morning dosing. The effects of such an approach on average 24-hour BP are more modest and less univocal, with a considerable between-center heterogeneity. Admittedly, the mechanisms underlying non-dipping condition have not been fully understood yet, and it is still a matter of debate whether restorating a dipping pattern may reduce the cardiovascular risk associated with non-dipping independently from the effects on 24-hour BP. Under this regard, evidence from a single trial strongly suggests that bedtime dosing of antihypertensive medications may greatly reduce cardiovascular morbidity in hypertensive patients. The provocative results of that trial deserve to be explored further in larger intervention trials.