Irbesartan/Hydrochlorothiazide Fixed Combination Therapy in Systemic Hypertension: An Open-Label Uncontrolled Trial

Objective: This open label, uncontrolled study was to assess 24-hour efficacy of once-daily combination of hydrochlorothiazide (HCTZ) plus irbesartan (IRB) in Taiwanese outpatient with mild-to-moderate HTN. Methods: Patients with pre-hypertension, stage I or II hypertension (HTN) (as defined by the Seventh Report of the National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, JNC VII) were eligible to participate. Twenty-four-hr ambulatory BP monitoring (ABPM) was performed twice in each patient before and after 8-weeks combitherapy. If supine DBP still＞95 mmHg at week 4 or 5, the dose was up titrated to high-dose IRB/HCTZ 300 mg/25 mg once daily (or 2 tablets of low-dose combination), or based on the decrease of BP. Results: A total of 25 patients (mean age, 54 years) were enrolled; 21 completed the study. Mean 24-hr systolic/diastolic BP after IRB/HCTZ combitherapy was significantly decreased compared with baseline BP (126±13/80±7 vs 148±14/92±9 mmHg (p＜0.001/0.001). Mean final dose of irbesartan /hydrochlorothiazide was 186±56/16±5mg daiy after 8 weeks of titration period. Mean daytime (6 A.M. to 6 P.M.) BP decreased from 150±14/94±9 to 127±13/ 81±7 mmHg, p＜0.001/0.001. Nighttime (6 P.M. to 6 A.M.) BP decreased from 142±15/89±10 to 125±18/80±11mmHg, p＜0.001/0.001). BP reduction was more pronounced during the day. After treatment, significant BP reduction was observed throughout 22 of the 24-hourly mean points. The circadian rhythm was preserved as indicated by similar BP standard deviations (18.5±3.4/16.0±3.0 vs 20.4±5/8.0±3.0 mmHg). Mean heart rate did not change. Two pts reported having dizziness and one frontal headache. Conclusions: Once-daily IRB/HCTZ combitherapy provided significant BP reduction throughout 22 of the 24 hourly mean points with preserved CR and was generally well tolerated in Taiwanese hypertension patients.