Efficacy and Safety of Amlodipine and Losartan in Patients With Essential Hypertension

Inclusion Criteria: * Patients aged between 18 and 75 * Patients with essential hypertension {95 mmHg ≤ sitDBP\< 115 mmHg at the end of placebo run-in treatment period} Exclusion Criteria: * Patients with mean sitSBP ≥ 200 mmHg * Patients with known hypersensitivity to Dihydropyridine or angiotensin II receptor blockers * Patients with secondary hypertension or suspected secondary hypertension * Patients with malignant hypertension * Patients who have received any medications with possible interactions with study drugs * Patients with uncontrolled diabetes * Patients with severe heart disease or severe cerebrovascular disease * Patients with clinically significant hematological test results, renal disease (serum creatinine) or liver disease (ALT or AST) * Patients with a history of malignant disease * Patients with a history of autoimmune disease * Women with a positive pregnancy test result, breast feeding or intention of pregnancy during the trial * Patients inappropriate to be included in study population due to other reasons at the discretion of the investigator