Effect of Tolvaptan on Cognitive Function in Cirrhosis

Inclusion Criteria: * Cirrhosis diagnosed by liver biopsy or radiological evidence of nodular cirrhotic liver or varices on endoscopy or laboratory features (platelet count \<150,000 with an AST/ALT ratio \>1). * History of HE controlled on lactulose and/or rifaximin * Last HE episode \>2 months prior to enrollment and \<2 episodes within 6 months * Mini-mental status exam score ≥25 * Serum sodium \<130mg/dl within the last 14 days and the day of enrollment * Availability of a caregiver * Able to undergo MR of the head Exclusion Criteria: * Uncontrolled HE manifested by MMSE \<25 * Alcohol abuse within 3 months * Illicit drug use within 3 months * Psychoactive drug use other than regularly scheduled anti-depressants or methadone. * Contraindication to MR examination (see attached MRI Safety Form) * Placement of a transjugular intra-hepatic portosystemic shunt (TIPS) * Creatinine Clearance less than 10 ml/min or undergoing hemodialysis * HIV infection * Use of azole medications * Pregnancy * Current use of tolvaptan, hypertonic saline or other medical therapies for hyponatremia