Study of Amiloride on Vascular Phenotypes in Young Adults With Prehypertension

Inclusion Criteria: * Prehypertensive: Having systolic BP between 120 to 139 mmHg and/or diastolic BP between 80 to 89 mmHg during screening visit. BP will be measured manually tree times at 10 minutes interval after subjects sit quietly for at least 5 minutes in a chair. The average of last two BP measurements will be taken into consideration. * Male or female of Caucasian or African-American origin. * No history of any major past and current medical illness (such as diabetes, renal disease, liver disease etc.) * Not taking any medication that affects blood pressure. Exclusion Criteria: * HbA1C \> 7.0 % during screening visit. * Serum potassium \> 5.5 mEq/L during screening and/or any testing visit due to risk of developing hyperkalemia. * Serum creatinine \> 1.5 mg/100 ml and/or creatinine clearance \< 50 ml/min\* (Glomerular Filtration Rate Estimate by Abbreviated MDRD Study Equation)35 during screening and/or any testing visit due to risk of developing renal dysfunction. * Female having positive pregnancy test during screening and/or any testing visit.