[The trough/peak ratio].

The trough-to-peak ratio expresses the quantitative relation between the antihypertensive effect of a drug or association of drugs measured at the end of a between-dose interval, and the maximum antihypertensive effect recorded during this interval. When this ratio is evaluated in responders, and a properly designed protocol that also takes blood pressure measurement into consideration is adopted, it becomes a reliable index of the duration-efficacy of antihypertensive therapy. For this reason, it constitutes a safety parameter required by the Food and Drug Administration to prevent the risk of drugs with shortlived action from being administered at excessive doses in the attempt to prolong the duration of drug action. In addition, a favorable trough-to-peak ratio (> 0.50 and preferably close to 1.0) is an index of homogeneous blood pressure control over a given between-dose interval. Pharmacological treatment that achieves this antihypertensive effect might be more efficient in preventing and/or causing regression of target organ damage and can improve patient compliance with antihypertensive therapy.