The purpose of this study is to determine the efficiency of Olmesartan medoxomile (OLMETEC®) alone or in combination with hydrochlorothiazide (OLMETEC PLUS®) in the reduction of arterial blood pressure in patients with light to moderate hypertension, and to evaluate the percentage of patients that reach treatment goals using this antihypertensive regimen.

α= 0.05. α's Z=1.96 β= 80%. β's Z=0.84 Estimated proportion of subjects to achieve optimal control of arterial hypertension= 83.2%

450 subjects are expected to be enrolled in the study of which 40 subjects will be enrolled in Venezuela.

Inclusion Criteria:

• Men or women 18 years of age or older
• Essential arterial hypertension Stade I and II according to JNC VII
• Signature of Informed Consent

Exclusion Criteria:

• Secondary arterial hypertension
• Pregnant woman or during lactancy
• Recent cardiovascular disease, as heart attack, unstable angina, or procedures of coronary revascularization on the previous six months.
• Acute Coronary Failure Syndrome on the previous six months.
• Chronic Ischemic Cardiopathy Treatment.
• Cerebral Vascular Disease on the previous six months.
• Alcoholism Story or use of drugs on the two previous years.
• Hepatic Disease Story
• Chronic Renal Failure defined by a serumal creatinine higher than 2mg/dl
• Albuminuria higher than 1gr.
• Known Allergy to blockers of angiotensine II receptors.
• Neoplasmic Malignant Disease included leukemia and the lymphoma (Skin basocellular cancer is not included)
• Auto Immune Disorders as systemic erythematosus lupus.
• Non attachment to medical treatments history.
• Patients sharing some clinical investigation essay on the last 3 months.
• Congestive heart failure under previous treatment with ECA inhibitors.
• Allergy to thiazidic diuretics.
• Angioedema History
• Use of drugs that affect potassium secretion, as diuretic savers of potassium, angiotensine enzyme inhibitor, betablockers, non-steroid anti-inflammatory drugs.
• Potassium consumption orally

Patients in Venezuela with arterial hypertension Stade I or Stade II