Efficacy and Safety of a Therapy Change From Candesartan 32 mg to Fixed Combination of Olmesartan 40 mg/Amlodipine 10 mg

Inclusion Criteria: * male or female patients \>= 18 years of age * essential hypertension, i. e. systolic office bp \>= 140 mmHg for pre-treated patients or \>= 160 mmHg for untreated patients at screening visit and \>= 160 mmHg at end of wash-out * signed IC Exclusion Criteria: * systolic office bp \> 180 mm Hg at screening visit * known hypertensive retinopathy GIII or IV * recent (\< 4 weeks ago) myocardial infarction or indication for coronary or peripheral revascularisation * type I diabetes or poorly controlled (HbA1c \>= 8) type II diabetes * chronic heart failure NYHA III or IV * prior stroke or TIA * creatinine clearance \< 60 ml/min or condition after kidney transplant * moderately or severely impaired liver function (ALT or AST or bilirubin more than double normal value) * women of childbearing potential without highly effective contraception, pregnant or breastfeeding women * concomitant therapy with lithium * hemodynamically relevant mitral or aortic valve stenosis (\>= II°) or hypertrophic obstructive cardiomyopathy * concomitant therapy with strong CYP3A4 inhibitors or inductors * african patients * concomitant severe psychiatric condition that might impair proper intake of study medication * life expectancy \< 6 months * night shift workers * known other mandatory indication for treatment with antihypertensive medications * parallel participation in other clinical trials