A new study published in Hepatology Research aimed to confirm the efficacy and safety of rifaximin in the treatment of hepatic encephalopathy (HE).

Here, two prospective, randomized studies – a phase II/III study and a phase III study, were conducted wherein patients with grade I or II HE and hyperammonemia were included. The phase II/III study was carried out at 37 institutions in Japan, where eligible patients were randomized to the rifaximin group (1200 mg/day) or the lactitol group (18-36 g/day). The phase III study included the same patients previously enrolled in the phase II/III study, and they were all treated with rifaximin (1200 mg/day) for 10 weeks.

In the phase II/III study, 172 patients were enrolled. The findings revealed that blood ammonia (B-NH3) concentration was significantly improved in the rifaximin group, but the difference between the two groups was not significant. While the portal systemic encephalopathy index (PSE index), including HE grade, was significantly improved in both groups. In the phase III study, 87.3% of enrolled patients completed the treatment. It was observed that the improved B-NH3 concentration and PSE index were well maintained from the phase II/III study during the phase III study. On the other hand, the use of rifaximin did not lead to any serious adverse drug reaction.

Hence, it was inferred that rifaximin is efficacious and well-tolerated in patients with HE and hyperammonemia.