Normal values for 24-hour blood pressure (BP) have not been well characterized. However, it is believed that the maintenance of normal blood pressure control is a desirable feature of an antihypertensive agent. This is particularly important with respect to the drug's ability to (1) maintain circadian variation, albeit from a lower baseline, (2) lower BP throughout the 24 hours, (3) avoid the development of postural hypotension, (4) avoid decreases in BP sufficient to precipitate an ischemic event, (5) and to reduce BP variability toward the normal BP limits.