 - Patients on antihypertensive medication should discontinue their antihypertensive treatment for at least 4 weeks. During the 4 weeks run-in period, all patients should have 2 clinic visits. At each visit, blood pressure will be measured 3 times consecutively. The average of these 6 readings from 2 clinic visits should be in the range of 140-180 systolic or 90-110 diastolic mm Hg. 24-h mean blood pressure should be equal to or higher than 130 mm Hg systolic and 80 mm Hg diastolic. 