Abnormalities of glucose, insulin and lipoprotein metabolism are common in patients with hypertension, and these metabolic abnormalities are reported to be related to insulin resistance. Therefore, whenever treating such patients, antihypertensive agents that may have the added effect of improving insulin resistance should be selected. CinalongTM (Cilnidipine) is expected to improve metabolic syndrome as well as insulin resistance by its dual effects on L and N-type calcium (Ca) channels. In this study, the researchers investigate the effects of CinalongTM on insulin resistance and other metabolic related factors.

• Multi-center, randomized, prospective, double blind, active control, parallel study
• Superiority study (Treatment group - Cilnidipine/Control group - Nifedipine)
• Measure the effects of Cinalong(TM) after 3 month and 12 month-application

Inclusion Criteria:

1. Men or women, 30-65 years of age having essential hypertension with metabolic syndrome

2. At Screening and Visit 1, blood pressure should be: sitting systolic blood pressure (SiSBP) >=140 mmHg or sitting diastolic blood pressure (SiDBP)>= 90 mmHg and two or more of the following criteria should apply.

   • Abdominal obesity: waist circumference >= 90 cm in men and >= 80 cm in women
   • Hypertriglyceridemia:. >=150 mg/dl (1.695 mmol/l)
   • Low HDL cholesterol: < 40 mg/dl (1.036 mmol/l) in men and < 50 mg/dl (1.295 mmol/l) in women
   • High fasting glucose: >= 110 mg/dl (6.1 mmol/l)

Exclusion Criteria:

1. Secondary hypertension
2. Malignant hypertension