The Effect of Nitrendipine/Atenolol Combination on Blood Pressure Variability.

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.