Effect of High and Low Sodium Diets on Blood Pressure in Hypertensive Patients Treated With Aliskiren

• Mean 24 Hour Ambulatory Diastolic Blood Pressure (MADBP) in Systolic Hypertensive Patients Treated With Aliskiren (300 mg) for 4 Weeks on a High Sodium Diet Versus 4 Weeks on a Low Sodium Diet [ Time Frame: Week 4 and week 8 (4 weeks after crossover) ] [ Designated as safety issue: No ]
  To evaluate the mean 24 hour ambulatory diastolic blood pressure (MADBP) in systolic hypertensive patients treated with aliskiren (300 mg) for 4 weeks on a high sodium diet versus 4 weeks on a low sodium diet. [At week 4 patients crossed over from low to high sodium diet and vice versa for 4 weeks. MADBP for patients on high sodium diet versus low sodium diet was also analyzed at week 8 (4 weeks after crossover).]
• Percentage of Responders Defined as MASBP <130 mm Hg or a Decrease From Baseline in MASBP of ≥20 mm Hg in Systolic Hypertensive Patients Treated With Aliskiren (300 mg) for 4 Weeks on a High Sodium Diet Versus 4 Weeks on a Low Sodium Diet [ Time Frame: Week 4 and Week 8 (4 weeks after crossover) ] [ Designated as safety issue: No ]
  To evaluate the percentage of responders defined as MASBP < 130 mm Hg or a decrease in MASBP from baseline of ≥20 mm Hg in systolic hypertensive patients treated with aliskiren (300 mg) for 4 weeks on a high sodium diet versus 4 weeks on a low sodium diet. [At week 4 patients crossed over from low to high sodium diet and vice versa for 4 weeks. Percent response for patients on high sodium diet versus low sodium diet was also analyzed at week 8 (4 weeks after crossover).]

• Change in mean 24-hour ambulatory diastolic blood pressure on aliskiren 300 mg for 4 weeks on a high sodium diet versus 4 wks on a low sodium diet.
• Responder rate defined as a drop in systolic blood pressure (SBP) of 20 mmHg or a mean 24-hour ambulatory SBP of < 130 mmHg from baseline on aliskiren 300 mg for 4 weeks on a high sodium diet versus 4 weeks on a low sodium diet.

This study will compare the effects of high and low level sodium (salt) diets on blood pressure in patients with hypertension (high blood pressure) who are taking aliskiren 300 mg.

• Experimental: Diet Sequence Low/High Sodium
  Patients on low sodium diet ( <= 100 mmol/day) for the first 4 weeks and high sodium (>= 200 mmol/day) diet for the next 4 weeks. [with Aliskiren 300 mg]
  Intervention: Drug: Aliskiren
• Experimental: Diet Sequence High/Low Sodium
  Patients on high sodium (>= 200 mmol/day) diet for the first 4 weeks and on low sodium diet ( <= 100 mmol/day) for the next 4 weeks. [with Aliskiren 300 mg]
  Intervention: Drug: Aliskiren

Inclusion Criteria:

• Male or female outpatients 18-60 years old
• Patients with systolic hypertension who met the 24 hour Ambulatory Blood Pressure Monitoring (ABPM) criteria (ABPM mean daytime Systolic Blood Pressure (SBP) >= 135 mmHg and < 160 mmHg)

Exclusion Criteria:

• Overt heart failure (HF) or a history of heart failure within preceding 6 months.
• Unstable angina pectoris.
• Type 1 or Type 2 diabetes mellitus or abnormal hemoglobin A1c(HbA1c)
• Body mass index (BMI) > 30 kg/m2
• Subjects taking more than 2 antihypertensive medications.
• Use of other investigational drugs within 30 days of the time of enrollment
• Use of Tamsulosin hydrochloride and other alpha blockers.
• Use of Antiarrhythmic drugs, including digoxin.
• History of MI or cardiovascular attack (CVA) within the preceding 6 months.
• History of malignancy of any organ system, treated or untreated, within the past 5 years with the exception of localized basal cell carcinoma of the skin
• Pregnant or nursing (lactating) women