Objective:

• To evaluate the antihypertensive efficacy of two brands of nifedipine 30mg in patients with hypertension.
• To assess the safety of 8 weeks of therapy with two brands of nifedipine 30mg in patients with hypertension.
• To study flow-mediated dilatation and oxidative stress in nonsmoker with essential hypertension but without diabetes mellitus or dyslipidemia.

Study Design:

• Head-to-head, randomized and parallel design.
• A total of 60 patients with a clinically confirmed diagnosis of hypertension will provide 30 available patients in each treatment group.
• The drugs and dosage will be as follows:

Group A: nifedipine 30-60mg once daily (Nifecardia, CCPC) Group B: nifedipine 30-60 mg once daily (Adalat OROS, Bayer)

Method:

After washout period, the eligible patients will randomly be allocated to receive two brands of nifedipine 30 mg once daily. Each patient will receive two times of ambulatory blood pressure measurement (ABPM) at both entrance and final stages of the study. The patients will also undergo complete clinical evaluation. Therapy dosage will be started at a dose of nifedipine 30 mg once daily. Dosage will be adjusted if systolic blood pressure greater than 140 mmHg or diastolic blood pressure greater than 90 mmHg by office measurement after 4 weeks of treatment. Nifedipine will be increased to 60 mg once daily. The Ambulatory blood pressure measurement will be set to take reading at 1-hour intervals during the 24 hours assessment.

Physical examination included the measurement of heart rate and blood pressure. The value will be read on Visit 1 and 3-12 hours after the last dose of nifedipine. Routine laboratory test includes hematology, blood chemistry and urinalysis. Hematology test and fasting blood chemistry test will be measured immediately before the start of treatment and after 8 weeks’ treatment or at time of discontinuation. Thiobarbituric acid–reactive substances (TBARS) in patient plasma were measured for oxidative stress and endothelium-dependent flow-mediated vasodilation will also be evaluated. Possible concomitant medication will remain constant throughout the study. The physician will question the patients as to their compliance at each visit. If compliance dose not reach 80%, the subject will be dropped out.