Ambulatory twenty-four-hour blood pressure measurements in pharmacological studies.

Until a few years ago, only casual blood pressure measurements were used in the diagnosis and treatment of arterial hypertension in clinical practice and in pharmacological studies. The development of portable lightweight devices for 24-h ambulatory blood pressure measurement has proved a substantial step towards reducing the potential pitfalls of casual blood pressure measurements. Ambulatory monitoring of blood pressure can improve pharmacological trials by excluding patients in whom blood pressure is elevated only in the clinic environment, and by increasing the accuracy and reproducibility of blood pressure values. Twenty-four-hour blood pressure measurement has great advantages for trials investigating the time-course of a particular drug, since the 24-h blood pressure rhythm is fully monitored. However, internationally accepted normal values for 24-h blood pressure measurements are required, and the interpretation of results obtained with this method needs to be standardized before the technique can be routinely used in antihypertensive drug trials.