Monotherapy-Controlled Study of Nifedipine Gastrointestinal Therapeutic System and Candesartan Cilexetil in Combination in Subjects With Essential Hypertension Inadequately Controlled on Candesartan Cilexetil

* Inclusion Criteria: * Male and female subjects 18 years or older are eligible. * At Visit 0, subjects not treated with antihypertensive medications are to have MSSBP (mean seated systolic blood pressure) of \>/= 160 mmHg and \< 200 mmHg, and 24 hours MASBP (mean ambulatory systolic blood pressure) \>/= 130 mmHg; those subjects treated with antihypertensive medication are to have MSSBP \>/= 150 mmHg and \< 200 mmHg as measured by a calibrated electronic BP measuring device * At Visit 3,subject must have MSSBP \>/= 140 mmHg before randomization. * Women of childbearing potential and men must agree to use adequate contraception other than hormonal contraceptives when sexually active. This applies since signing of the IC (informed consent)form until the last study drug administration. * Exclusion Criteria: * Mean seated systolic blood pressure (MSSBP) \>/= 200 mmHg and/or mean seated diastolic blood pressure (MSDBP) \>/= 120 mm/Hg * Mean seated diastolic blood pressure (MSDBP) \< 60 mm/Hg * Differences greater than 20 mmHg for systolic blood pressure (SBP) and 10 mmHg for diastolic blood pressure (DBP) are present on 3 consecutive blood pressure readings at visit 0 * Evidence of secondary hypertension such as coarctation of the aorta, pheochromocytoma, hyperaldosteronism, etc. * Cerebrovascular ischemic event (stroke, transient ischemic attack \[TIA\]) within the previous 12 months * History of hypertensive retinopathy - known Keith-Wagener Grade III or IV. Any history of heart failure, New York Heart Association (NYHA) classification III or IV * Severe coronary heart disease as manifest by a history of myocardial infarction or unstable angina in the last 6 months prior to visit 0 * Clinically significant cardiac valvular disease * Subjects with an aortic aneurysm that, in the opinion of the investigator, will be unsuitable to be enrolled in the study. * Type 1 diabetes mellitus (DM) or poorly controlled Type 2 DM as evidenced by glycosylated hemoglobin HbA1C of greater than 9% on visit 0