Effects of Nebivolol Versus Metoprolol Succinate on Endothelial Function

Inclusion Criteria: * Patients with mild to moderate essential hypertension (systolic BP 140-179 mmHg and/or diastolic BP 90-109 mmHg)\* * Male and female patients aged 30-65 years Newly diagnosed untreated patients or previously diagnosed patients who were without treatment at least two weeks prior to screening\* If patient has been taken previously antihypertensive medication the BP values are originated after untreated two weeks before randomization Exclusion Criteria: * Concomitant medication: Cyclic antidepressants, MAO inhibitors, corticosteroids * Diabetes I or II type (fasting venous plasma glucose \> 6.4 mmol/l) * Bronchial asthma and chronic obstructive airway disease * Body mass index \> 30 kg/m2 * Ischaemic heart disease (III, IV stage, Canadian Cardiovascular Society) * Clinically relevant heart failure (NYHA class II - IV) * Clinically relevant valve disease (physical examination) * Arrhythmias and conduction disturbances, requiring therapy, sinus bradycardia at rest \< 50 b/min, sick sinus syndrome, AV - block stage II - III * Secondary hypertension (urea \>8.3 mmol/l, creatinine \>120μmol/l (males), \>103 μmol/l (females), TSH \> 4.0mIU/l, free T4 \> 27 pmol/l) * Clinically relevant atherosclerotic disease of lower extremities * Acute inflammation (according to CRP \> 10mg/l) * Hypercholesterolemia (\> 6,5 mmol/l) * Allergic reaction to beta-blockers * Pregnant or breast-feeding women * History of hepatic, renal, metabolic or endocrine diseases * Smoking \> 10 cigarettes per day * Alcohol consumption \> 7 drinks per week (drink = 0,33 l beer, 120 ml wine or 30 ml strong alcoholic drink) * The patient has had surgery or disease of the gastrointestinal tract which, in the opinion of the investigator, may influence the absorption or elimination of the study drug. * The patient has a severe organic disorder that may interfere with the absorption, pharmacokinetics, or elimination of the study medication. * The patient has a comorbid condition that would be expected to result in death during the trial period (e.g., terminal cancer, AIDS). * The patient has chronic psychoses or behavioural conditions that would limit the ability of the patient to comply with the requirements of this study. * The patient has known hypersensitivity to Nebivolol, Metoprolol or hydrochlorothiazide related compounds. * Patient is enrolled in another clinical trial.