Efficacy of Switching from Kanamycin Sulfate to Rifaximin in Patients with Hepatic Cirrhosis

OBJECTIVE: This study evaluated the efficacy associated with switching to rifaximin in patients with hepatic cirrhosis receiving kanamycin sulfate for the treatment of hepatic encephalopathy and hyperammonemia. METHODS: We included 37 patients who switched from kanamycin sulfate to rifaximin at our institution from January 2017 to December 2018. The onset of hepatic encephalopathy and changes in blood ammonia values during a six-month period were retrospectively evaluated. RESULTS: There were 4 (11%) patients with hepatic encephalopathy at the time of switching from kanamycin sulfate to rifaximin. The cumulative incidence of hepatic encephalopathy was 3% and 16% at 3 and 6 months later, respectively. The blood ammonia levels at the time of switching to rifaximin and at 3 and 6 months later were 94 (range, 20-243) μg/dL, 95 (range, 33-176) μg/dL, and 81 (range, 32-209) μg/dL, respectively, and no significant changes were observed. However, in the 11 patients receiving an oral dose of <1,500 mg/day of kanamycin sulfate, the blood ammonia levels at the time of switching and at 3 and 6 months later were 136 (range, 35-243) μg/dL, 95 (range, 33-150) μg/dL, and 63 (range, 43-124) μg/dL, respectively. Furthermore, the blood ammonia levels significantly decreased at the time of the switching to rifaximin and at three and six months later (p=0.043 and p=0.011, respectively). CONCLUSION: Switching to rifaximin in hepatic cirrhosis patients receiving kanamycin sulfate to treat hepatic encephalopathy and hyperammonemia showed effects that were equivalent to or greater than the original therapy, thereby demonstrating the clinical efficacy.