Evaluation of pharmacotherapy by indirect ambulatory blood pressure monitoring in short- and long-term studies: review of the literature.

Over a period of 24 h, blood pressure and the heart rate vary according to a circadian rhythm of waking, sleeping and work periods and also according to stress factors. Thus, in clinical trials, blood pressure measurements that are taken only casually in the office may be inadequate to assess the potency and duration of antihypertensive drug effects. A number of studies have demonstrated that non-invasive 24-h ambulatory blood pressure measurement is generally free of any placebo effect. This method can simplify the design of trials to determine the efficacy of antihypertensive agents. Furthermore, a smaller number of patients is required for drug trials that use this type of monitoring, since the intrasubject variability in blood pressure is reduced compared with clinic measurements. Thus, indirect ambulatory 24-h blood pressure measurement is useful in assessing acute and long-term drug efficacy, and also the efficacy over 24 h after a single drug dose or a new form of drug application.