The patient recruitment and follow-ups were influenced with the pandemic of COVID-19

This trial evaluates the effects of Nifedipine GITS and Amlodipine besylate on blood pressure rhythm restoration and arterial stiffness in young and middle-aged non-dipper hypertensives. Half of participants will receive Nifedipine GITS, half of half will take medicine in the morning or at night. While the other half participants will take amlodipine besylate, whom will also be assigned taking medicine in the morning or at night. Ambulatory blood pressure monitoring and arterial stiffness examination will be performed before and after pharmaceutical intervention.

Written informed consent will obtained from all the participants. All the adverse reaction or adverse event, related or unrelated to the study drug, will be recorded in detail, including the occurrence time, symptoms and vital signs, degree, duration, laboratory test indexes, treatment methods and results, process, follow-up time, etc.

If serious adverse event occurs, study drugs should be stopped and necessary remedy should be delivered immediately. At the same time, the investigator must report it to the local drug supervision, medical ethics committee and China Food and Drug Administration.

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Inclusion Criteria:

• Mild to moderate (Office blood pressure : 140 mmHg =< systolic blood pressure (SBP) <180 mmHg and / or 90 mmHg =< diastolic blood pressure (DBP) <110 mmHg) , non-dipper (ambulatory blood pressure monitoring (ABPM): night-time mean SBP / day-time mean SBP >=0.9 and night-time mean SBP >=120 mmHg) hypertensive subjects, who is drug treatment-naive or previously treated but discontinued for 2 weeks or more
• The subject is voluntary to participate in the study and has signed the informed consent form

Exclusion Criteria:

• Known allergy to any component of Nifedipine and Amlodipine
• Office SBP >=180 mmHg and / or DBP >=110 mmHg in the screening period
• The patient who is taking calcium antagonists (monotherapy or combination with other drugs)
• Evidences of secondary hypertension
• History of cerebrovascular events, cardiac failure, serious coronary artery disease within 12 months
• Type 1 diabetes mellitus (DM)
• Severe liver diseases or renal insufficiency
• The pregnant woman, the woman who may be pregnant or plan to be pregnant, or the lactating woman
• The subject who needs to work at night (on night shift)
• Other reasons that the subject can not participate in the study