This is a multi-center, open-label, observational study. The aim of this study is to evaluate the efficacy of Nifedipine GITS on lowering blood pressure in Chinese adults with mild-to-moderate hypertension.

The primary aim of the study is to evaluate the efficacy of nifedipine gastrointestinal therapeutic system (GITS) on lowering blood pressure in Chinese adults with mild-to-moderate hypertension. The secondary aim of the study is to evaluate the efficacy of Nifedipine GITS on lowering blood pressure in hypertensive patients with different urinary sodium levels. Based on sample size estimation, the plan is to recruit 700 patients from 16 centers. At baseline, patients'demographic characters, disease history and anthropometric indices will be collected, laboratory tests will be performed for blood routine examination, urinalysis, renal function, hepatic function, urinary sodium and 24-hour urinary sodium. All eligible patients will be assigned to a treatment of Nifedipine GITS and followed up for 8 weeks. At 0 day, 2,weeks, 4 weeks and 8 weeks of the study, seated blood pressure, vital signs, medication and adverse events were collected. At the end of the study, 24-hour ambulatory blood pressure monitoring (ABPM) will be performed for all participants.

Inclusion Criteria:

• a seated systolic BP (SBP) ≥140 mmHg and <180 mmHg and/or a seated diastolic BP (DBP) ≥90 mmHg and <110 mmHg;
• an age ≥18 and ≤75 years;
• those who had not taken any BP-lowering medications in 1 month before the study.

Exclusion Criteria:

• a seated systolic BP (SBP) ≥180 mmHg and/or a seated diastolic BP ≥110 mmHg;
• secondary hypertension;
• diagnosed heart failure or stroke;
• Any of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) was above 1.5 times of it's normal value upper limit, Serum creatinine >177 µmmol/L (2mg/dL), or liver cirrhosis;
• subjects with carotid stenosis or systolic murmur
• subjects with a history of unstable angina pectoris, acute mycardial infarction, percutaneous transluminal coronary angiography or coronary artery bypass grafting in the past 6 months;
• subjects who were within lactation period, pregnant, or planning to become pregnant during the study;
• hypersensitive to Nifedipine GITS or with SAE;
• subjects who are participating in other clinical trials;
• considered not fit for the study due to other reasons according to the researchers (such as Malignant tumor, psyche or nervous system dysfunction, or special diseases).