1. Study name: The Effect of Nitrendipine/Atenolol Combination on Blood Pressure Variability.
2. Medicine: Nitrendipine/Atenolol; Nitrendipine; Atenolol.
3. Rationale: Blood pressure variability correlates with cardiovascular events and target-organ damage in hypertensive patients. Nitrendipine/Atenolol has obvious advantages in reducing blood pressure variability in hypertensive rats, but the effect of this combination on hypertensive patients is still unknown.
4. Objective: To evaluate the effect of nitrendipine/atenolol on blood pressure variability of patients with Grade 1 hypertension compared with nitrendipine or atenolol monotherapy.
5. Study design: This study is a cross-over, randomized, controlled clinical trial with two equally sized treatment groups: Nitrendipine/Atenolol (5mg/10mg); Nitrendipine (10mg) or atenolol (25mg).
6. Study population: Men and Women aged 30-65 years (n=32) meeting the inclusion/exclusion criteria.
7. Randomization and cross-over design: Eligible patients will be randomly divided into two groups. Half of patients will take nitrendipine/atenolol (5/10mg) once daily for 6 weeks first, and then evenly turn into nitrendipine (10mg) or atenolol (25mg) once daily for 6 weeks. Another half of patients will evenly take nitrendipine (10mg) or atenolol (25mg) first, and turn into nitrendipine/atenolol (5/10mg) next.
8. Follow up: 14 weeks.
9. Sample size: a total of 32 patients should be enrolled.
10. Timeline: After obtaining the approval of Ethics Committee of Ruijin Hospital in April 2021, recruitment will start. Patients enrollment and follow-up will be performed between June 2021 to June 2022.

1. Study name: The effect of Nitrendipine/Atenolol combination on blood pressure variability of patients with Grade 1 hypertension compared with nitrendipine or atenolol monotherapy.
2. Medicine: Nitrendipine/Atenolol (5/10mg tablet); Nitrendipine (10mg tablet); Atenolol (25mg tablet)
3. Rationale: Blood pressure variability correlates with cardiovascular events and target-organ damage in hypertensive patients. Nitrendipine/Atenolol has obvious advantages in reducing blood pressure variability in hypertensive rats, but the effect of this combination on hypertensive patients is still unknown.
4. Objective: To evaluate the effect of nitrendipine/atenolol on blood pressure variability of patients with Grade 1 hypertension compared with nitrendipine or atenolol monotherapy.
5. Study design: This study is a cross-over, randomized, controlled clinical trial with two equally sized treatment groups: Nitrendipine/Atenolol (5mg/10mg); Nitrendipine (10mg) or atenolol (25mg).
6. Study population: Eligible patients (n=32) should be men or women aged 30-65 years. Untreated patients diagnosed as essential hypertension, whose daytime systolic blood pressure ≥ 135mmHg and/or daytime diastolic blood pressure ≥ 85mmHg, and standard deviation (SD)≥13mmHg will be recruited.
7. Randomization and cross-over design: Eligible patients will be randomly divided into two groups. Half of patients will take nitrendipine/atenolol (5/10mg) once daily for 6 weeks first, and then evenly turn into nitrendipine (10mg) or atenolol (25mg) once daily for 6 weeks. Another half of patients will evenly take nitrendipine (10mg) or atenolol (25mg) first, and turn into nitrendipine/atenolol (5/10mg) next.
8. Follow up: 14 weeks. 1 week for screening period, 6 weeks for the first period of treatment, 1 week for wash-out period, and 6 weeks for the second period of treatment.
9. Sample size: a total of 32 patients should be enrolled.
10. Timeline: After obtaining the approval of Ethics Committee of Ruijin Hospital in April 2021, recruitment will start. Patients enrollment and follow-up will be performed between June 2021 to June 2022.
11. Organization: The Centre for Epidemiological Studies and Clinical Trials, Ruijin Hospital, Shanghai, China.

Inclusion Criteria:

• Men or Women.
• Aged 30-65 years.
• Ambulatory systolic blood pressure ≥ 135 mmHg and/or diastolic blood pressure ≥ 85 mmHg.
• Ambulatory daytime systolic blood pressure standard deviation (SD)≥13mmHg.
• Never took antihypertensive drugs.
• Signed the written consent.

Exclusion Criteria:

• Under antihypertensive treatments.
• Clinic systolic blood pressure ≥ 160mmHg and/or diastolic blood pressure ≥ 100mmHg.
• Contraindications to the treatment of drugs, including hypersensitivity reaction, bradycardia, asthma, etc.
• Any cardiovascular disease except hypertension.
• Suspected or confirmed secondary hypertension.
• Poor compliance.