The aim of present study is to evaluate the efficacy and safety of two dose combination of S-Amlodipine/Telmisartan (2.5/40mg, 2.5/80mg and 5/80mg) compared with S-Amlodipine monotherapy (2.5mg and 5mg) in patients with Stage 2 hypertension.

• In patients with Stage 2 hypertension to determine the efficacy and safety of S-Amlodipine/Telmisartan (2.5/40mg, 2.5/80mg and 5/80mg) or S-Amlodipine monotherapy (2.5mg and 5mg) during 10 weeks.
• This study is consist of placebo run-in period(2 weeks_single blind) and treatment period(10 weeks_double blind.

Inclusion Criteria:

• age 18 years or older

• at the screening visit

  • antihypertensive drugs not taking: 160mmHg ≤ sitSBP < 200mmHg
  • antihypertensive drugs taking: 140mmHg ≤ sitSBP < 180mmHg

• at the randomization visit(160mmHg ≤ sitSBP < 200mmHg)

• willing and able to provide written informed consent

Exclusion Criteria:

• mean sitting DBP ≥ 120mmHg or mean sitting SBP ≥ 200mmHg at the screening visit and randomization visit

• for the past four weeks based on beginning of administration, patients took over four antihypertensive drugs

• known or suspected secondary hypertension(ex. aortic coarctation, Primary hyperaldosteronism, renal artery stenosis, pheochromocytoma)

• has severe heart disease(Heart failure NYHA functional class 3, 4), ischaemic heart diseasesstatus need to treatment, myocardiopathy, Valve disease, arrhythmia and so on and operated Coronary angioplasty

• has cerebrovascular disease as cerebral infarction, cerebral hemorrhage within 6 months

• Type I Diabetes Mellitus, Type II Diabetes Mellitus with poor glucose control as defined by fasting glucosylated hemoglobin(HbA1c) > 8%)

• known severe or malignant retinopathy

• defined by the following laboratory parameters:

  • hepatic dysfunction(AST/ALT > UNL X 3)
  • renal dysfunction(serum creatinine > UNL X 1.5)
  • hypopotassemia(K < 3.0mmol/L) or hyperpotassemia (K>5.5 mmol/L)

• acute or chronic inflammatory status need to treatment

• need to additional antihypertensive drugs during the study

• need to concomitant medications known to affect blood pressure during the study

• history of angioedema related to ACE inhibitors or Angiotensin II Receptor Blockers

• known hypersensitivity related to either study drug

• history of drug or alcohol dependency within 6 months

• any surgical or medical condition which might significantly alter the absorption, distribution, metabolism, or excretion of investigational products(ex. gastrointestinal tract surgery such as gastrectomy, gastroenterostomy or bypass, active inflammatory bowel syndrome within 12 months prior to screening, gastric ulcers need to treatment, gastrointestinal/rectal bleeding, impaired pancreatic function such as pancreatitis, obstructions of the urinary tract or difficulty in voiding)

• administration of other study drugs within 4weeks prior to randomization

• premenopausal women(last menstruation < 1year) not using adequate contraception, pregnant or breast-feeding

• history of malignancy including leukemia and lymphoma within the past 5 years

• in investigator's judgment