After a 2-week placebo washout , 361 treated hypertensive patients [ office sitting diastolic BP ( DBP ) , 90mmHg ] , aged 18-75years , were randomized double blind to 18-week treatment with zofenopril 30mg plus HCTZ 12.5 mg or irbesartan 150mg plus HCTZ 12.5 mg once daily , in an international , multicenter study .