- Hypertensive at screening: Diastolic blood pressure (DBP) 95 - 115 mm Hg and / or systolic blood pressure (SBP) >= 160 mm Hg on no therapy or on monotherapy. If currently on monotherapy, DBP could have been < 95 mm Hg and SBP < 160 mm Hg, but the patient must have been experiencing unacceptable side effects from their current treatment. Patient must then be able to stop treatment for the placebo run in phase of four weeks without endangering their health (at investigator's discretion)