Week 16 - Visit 8 - Post-Washout visit: Subjects will return to the GCRC for an interval history, pill count, blood pressure check, BMP and CBC, if indicated. If BP and renal function permit, the patient will receive their crossover medication (placebo x 2 weeks or aliskiren 150mg po, qd x 2 weeks). If applicable, a urine pregnancy test will be done for child bearing age females.