Retrospective cross-sectional pilot study of rifaximin dosing for the prevention of recurrent hepatic encephalopathy

Standard treatment for hepatic encephalopathy (HE) includes medications that reduce ammonia and bacterial translocation in the gut. Rifaximin can be used off-label for the reduction of overt HE. The study purpose was to determine efficacy of traditional rifaximin dosing (400 mg three times daily) compared with newer dosing (550 mg twice daily) via readmission rates for the prevention of recurrent HE. This was a retrospective, observational, cross-sectional pilot study conducted in a tertiary medical center. A total of 226 patients 18–89 years of age with documentation of HE via ICD-9 code who started rifaximin therapy while inpatient between April 2009 and June 2014 were evaluated. Data collected included rifaximin dosing, other medications used to treat HE, duration of therapy, time to readmission, and various laboratory values. There were no differences in readmission rates at 30 days, 60 days, or 6 months between treatment groups. Additionally, there was no difference in the odds of readmission between the treatment groups (OR = 0.77, 95% CI: [0.201, 4.365], P = 0.718). Patients had a low overall probability of readmission over the observational period. Based on average wholesale price data, the cost for a 9-day supply of rifaximin for the 400-mg dosing regimen is $952.56 versus $605.16 for the 550-mg dosing regimen. The rifaximin 550-mg dosing strategy should be utilized in hospitalized patients for the prevention of recurrent HE as there was no difference in readmission rate or time to readmission between dosing groups. The 550-mg regimen had a lower acquisition cost for a 9-day duration of treatment in the studied institution.