Nifedipine and barnidipine act as calcium channel blockers, and are widely prescribed for pressure control of prehypertension and stage 1 hypertension.

CYP3A4 is responsible for the metabolism of nifedipine and nifedipine, while the contribution of CYP3A5 remains ambiguous. This study is aimed to analyze the association between antihypertensive effects of nifedipine as well as barnidipine and single nucleotide polymorphisms of CYP3A4, CYP3A5 and calcium channels.

For each drug, 20 patients will be enrolled. Patients' blood pressure and heart rates will be measured at first visit, followed by visits at week4 , week 8 and week 12. Blood samples will be drawn at week 4 and week 12 for following analyses of drug plasma concentrations. SNPs in CYP3A4, CYP3A5 and calcium channel v 1.2 will be genotyped using SNPstream.

The differences in the decrease of blood pressures and the durg plasma concentrations between genotypes will be analyzed.

Inclusion Criteria:

• 20~90 years old patient
• mild to moderate hypertensive patients
• can finish this study
• can sign agreement

Exclusion Criteria:

• severe hypertension
• Heart failure, Arrhythmia
• Liver or kidney failure
• pregnant women
• allergy to dihydropyridines
• attend other clinical trials in past 3 month

Hypertension patients living in Taiwan