7. a screening BUN or creatinine value that is >1.5 times the upper limit of normal, or liver function tests that are >2 times the upper limit of normal 8. any other screening laboratory test values that the Investigator or Sponsor considers clinically significant that would impact the outcome of the study or the safety of the patient 9. using proton pump inhibitors or antacids 10. pregnant (post-menarchal female patients should be made aware that pregnancy testing will occur during the study, and that if they are sexually active they must take appropriate steps to ensure they do not become pregnant during the study) 11. a positive urine screen for drugs of abuse 12. participated in another clinical trial involving active intervention within 30 days prior to randomization.