Primary: 1. To compare the change in forearm vascular resistance following a 12-week regimen of irbesartan/hydrochlorothiazide versus irbesartan 2. To assess changes of serum proinflammatory cytokine, markers of cardiovascular risks, oxidative stress and circulating adhesion molecule including thiobarbiturate acid reactive substances (TBARS), C-reactive protein (CRP), interleukin 6 (IL-6), and vascular cell adhesion molecule 1 (VCAM-1). Secondary: 1. To compare the reduction in office blood pressure following a 12-week regimen of irbesartan/hydrochlorothiazide versus irbesartan 2. To compare the response rate (defined as office Systolic blood pressure(SBP)/diastolic blood pressure (DBP) reduce more than 10mmHg from baseline), and BP controlled rate (defined as SBP<140 mmHg and /or DBP<90 mmHg) 3. To ascertain the safety and tolerability of irbesartan / hydrochlorothiazide versus irbesartan when administered once daily 4. To determine whether angiotensin II type 1 (AT-1) receptor gene polymorphisms (including A1166C gene with about 4% of the minor allele frequency in Chinese population and other single nucleotide polymorphisms with a higher frequency of about 10% of minor allele) is related to reduction of BP
Name: Irbesartan/Hydrochlorothiazide
Description: Administration of irbesartan 150 mg/day + hydrochlorothiazide 12.5 mgType: Drug1 2
Name: Irbesartan
Description: Administration of irbesartan 150 mg/dayType: Drug1 2
Allocation: Randomized
Crossover Assignment
There is one SNP
To compare the reduction in office blood pressure following a 12-week regimen of irbesartan/hydrochlorothiazide versus irbesartan 2. To compare the response rate (defined as office Systolic blood pressure(SBP)/diastolic blood pressure (DBP) reduce more than 10mmHg from baseline), and BP controlled rate (defined as SBP<140 mmHg and /or DBP<90 mmHg) 3. To ascertain the safety and tolerability of irbesartan / hydrochlorothiazide versus irbesartan when administered once daily 4. To determine whether angiotensin II type 1 (AT-1) receptor gene polymorphisms (including A1166C gene with about 4% of the minor allele frequency in Chinese population and other single nucleotide polymorphisms with a higher frequency of about 10% of minor allele) is related to reduction of BP Forearm vascular resistance. --- A1166C ---