At the screening visit, patients who fulfilled the entrance criteria and had given written informed consent entered a placebo running period where they discontinued antihypertensive medication for two weeks. During that period, Adalat 5mg could be given for emergency. At the end of placebo running period those patients became hypertensive (i.e., SBP between 130-180mmHg or DBP between 80-110mmHg) were randomized into either treatment group. For those patients remaining normotensive continued to be on placebo run-in for another two weeks (10 - 14 days). After the two-week (10 - 14 days) placebo run-in period those patients became hypertensive were randomized into either treatment group. However for those patients remaining normotensive were excluded from the study. After randomization into either arm, patients entered four months treatment period. The dosage adjustment were proceed in order to reach the best effect. During the treatment period there was a monthly visit to assess the response of the patients.
The starting dose of Amtrel® was 1 capsule (contains 1/2 tablet) (amlodipine / benazepril hydrochloride 2.5 mg/ 5 mg) every morning and could be adjusted up to 2 capsules (contains 1 tablet per capsule) (amlodipine / benazepril hydrochloride 10 mg/ 20 mg) every morning if patients did not achieve the criteria of SBP\<130 mmHg and DBP\< 80 mmHg during treatment period.
The starting dose of Co-Diovan® was 1 capsule (contains 1/2 tablet) (valsartan/ hydrochlorothiazide 40 mg/ 6.25 mg) every morning and could be adjusted up to 2 capsules (contains 1 tablet per capsule) (valsartan/ hydrochlorothiazide 160 mg/ 25.0 mg) every morning if patients did not achieve the criteria of SBP\<130 mmHg and DBP\< 80 mmHg during treatment period.
All randomized patients attended monthly clinic visits for the 16-week treatment period. At week 4 (Visit 3), all patients were force-titrated to 1 capsule (1 tablet per capsule) for 4 weeks. Subsequently, those patients did not achieve the target blood pressure (SBP\<130 mmHg and DBP\<80 mmHg) were titrated monthly to next dose level (2 capsule per day).
