BP-EASE -Effectiveness of Losartan 50 mg/Hydrochlorothiazide (HCTZ) 12.5 mg Versus Valsartan 80 mg/HCTZ 12.5 mg Titrated as Needed in Patients With Essential Hypertension Not Controlled on Monotherapy (0954A-333)

Inclusion Criteria: * An Adult Patient 18 to 75 Years Of Age * Patient with essential hypertension receiving an antihypertensive agent in monotherapy for at least 4 weeks for whom the antihypertensive agent can (and will) be discontinued and whose blood pressure is not controlled: * Either systolic or diastolic blood pressure \> 140/90 mm Hg up to 180/110 mm Hg (inclusive) * Either systolic or diastolic blood pressure \> 130/80 mm Hg up to 160/100 mm Hg (inclusive) for diabetic patients * Patient is male or a female who is highly unlikely to conceive as she falls into one of the categories listed below: * Surgically sterilized female * Postmenopausal female \> 45 years of age with \> 2 years since her last menses * Non-sterilized pre-menopausal female who agrees to: (1) use 2 adequate methods of contraception to prevent pregnancy \[either 2 barrier methods or a barrier method plus a hormonal method\]; or (2) abstain from heterosexual activity throughout the study starting with Visit 1 and for 14 days after the last dose of study medication; or (3) only engage in heterosexual activity with surgically sterilized male partner(s) throughout the study starting with Visit 1 and for 14 days after the last dose of study medication * Patient judged to be in otherwise good, stable health on the basis of medical history and physical examination Exclusion Criteria: * Known secondary hypertension of any aetiology (e.g., uncorrected renal artery stenosis, malignant hypertension, or hypertensive encephalopathy) * Patient Needing An Initiation Of A Lipid Lowering Agent Or A Modification Of His Lipid Therapy At Visit 1 Or During The Study Period (12 Weeks) * Patient taking allopurinol * Patient Previously Shown To Be Intolerant To Any Component Of Losartan Valsartan, Or HCTZ Or With A Documented History Of Angioedema/Anaphylaxis * Patient With Confirmed Clinically Significant Renal Or Hepatic Dysfunction And/Or Electrolyte Imbalance Laboratory Test Within The Last 3 Months Prior To Visit 1: Serum Creatinine \> 130 Umol/L Or Creatinine Clearance \< 45 Ml/Min, Aspartate transaminase (AST) \> 2 Times Above The Normal Range, Alanine transaminase (ALT) \> 2 Times Above The Normal Range, Serum Potassium \< 3.5 Or \> 5.5 Meq/L * Patient with osteoarthritis who has undergone hip or knee replacement within the last 4 months * Patient with chronic inflammatory conditions such as rheumatoid arthritis, lupus, inflammatory bowel disease and those that need a chronic inflammatory therapy such as prednisone or other steroid agents * Patient with symptomatic heart failure (classes 3 and 4) * Patient with a history of stroke within the last 6 months * Patient with coronary heart disease: has undergone percutaneous coronary angioplasty, has had coronary artery bypass, has had past myocardial infarction, all that occurred less than 6 months prior to visit 1 or has unstable angina * Patient having participated in an investigational drug program in the last 30 days (prior to Visit 1) * Unable or unwilling to comply with the protocol, therefore likely to leave the trial before its completion * Patient intends to move or to vacation away from home during the course of the study which would interfere with the scheduled visits.