The aim of present study is to evaluate the efficacy and safety of Carvedilol SR versus Carvedilol IR in Patients With Essential Hypertension

• In patients with Essential hypertension to evaluate the efficacy and safety of Carvedilol SR (32mg, 64mg) or Carvedilol IR (25mg QD, 25mg BID) during 8 weeks.
• This study is consist of placebo run-in period(2~4 weeks_single blind) and treatment period(8 weeks_double blind).

Inclusion Criteria:

• age 18 years or older

• at the screening visit(visit 1)

  • antihypertensive drugs not taking: 90mmHg ≤ mean sitDBP ≤ 109mmHg and mean sitSBP < 180mmHg
  • antihypertensive drugs taking: mean sitDBP ≤ 104mmHg and mean sitSBP < 180mmHg

• at the randomization visit(visit 2): 90mmHg ≤ mean sitDBP ≤ 109mmHg and mean sitSBP < 180mmHg

• willing and able to provide written informed consent

Exclusion Criteria:

1. At Screening, difference in measured blood pressure of the selected arm(sitDBP ≥ 10mmHg or sitSBP ≥ 20mmHg)

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

3. Type I Diabetes Mellitus, Type II Diabetes Mellitus with poor glucose control as defined by fasting glucosylated hemoglobin(HbA1c > 9%)

4. Corresponding to the following

   • has severe heart disease(Heart failure NYHA functional class 3, 4)
   • ischaemic heart diseases within 6 months (unstable angina or myocardial infarction)
   • myocardiopathy
   • Cor pulmonale
   • aortic stenosis , aortic valvular stenosis , mitral stenosis
   • abnormality of the conduction system as 2nd degree AV block, Complete AV block, Sick Sinus Syndrome, Sinus Block(In particular, pulse <50beats / min)
   • has heart attack with complication.

5. has cerebrovascular disease as cerebral infarction, cerebral hemorrhage within 6 months

6. has edema glottitis, allergic rhinitis, Respiratory diseases as Asthma, Chronic Obstructive Pulmonary Disease.

7. Peripheral circulatory disturbance( ex. Raynaud syndrome, intermittent claudication)

8. Fluid retention or overload to required intravenous inotropes.

9. known severe or malignant retinopathy(retinal hemorrhage, visual disturbance, Retinal microaneurysms and so on within 6 months)

10. defined by the following laboratory parameters:

    • hepatic dysfunction(AST/ALT ≥ UNL X 3)
    • renal dysfunction(serum creatinine ≥ UNL X 2)

11. 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)

12. history of drug or alcohol dependency within 6 months

13. premenopausal women(last menstruation < 12 months) not using adequate contraception, pregnant or breast-feeding

14. chronic inflammatory status need to treatment

15. known hypersensitivity related to carvedilol

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

17. administration of other study drugs within 28 days prior to the first IP administration

18. in investigator's judgment