 Clinical blood pressure and BW, biological and hormonal evaluations were conducted at baseline and at the end of each treatment period, between 9:00 and 10:00 hours, two hours after a light calcium-free breakfast and a one hour-rest in a reclined position. At the end of the baseline and washout periods and each treatment period, two successive 24-h urine collections were obtained, and a morning spot urine sample was collected on the day of investigation for measurements of urine electrolytes Na, K, calcium and creatinine. Hematocrit, and electrolyte, creatinine, proteins, renin and aldosterone concentrations were measured in blood samples. Additionally, Blood Pressure, Body Weight and biological tolerance was assessed 15 days after each increase in the HCTZ dose. 