Second-generation calcium antagonists and ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) is a particularly useful method for evaluating the effects of antihypertensive drugs. ABPM allows the therapeutic effect of an agent to be assessed continually by a large number of measurements, and the greater number of readings contributes to the higher degree of reproducibility associated with ABPM compared to other methods for measuring blood pressure. ABPM also enable measurements to be taken in "real-life" situations and removes the problem of observer bias. The number of patients required for clinical studies can be significantly reduced by using ABPM. It is still essential, however, to identify "white coat" subjects, placebo responders, and patients who do not respond to the treatment. ABPM studies have demonstrated that the novel dihydropyridine calcium antagonist, lacidipine, significantly reduces both systolic and diastolic blood pressures over a 24-h period, both during the day and at night. Furthermore, although the trough-to-peak ratios of many calcium antagonists have been shown to fall below the recommended level of 50%, lacidipine has a ratio above 60%. Other ABPM studies have also shown that lacidipine can correct the 'early morning increase' in blood pressure without effecting the 24-h nycthemeral profile.