Evaluation of rifaximin, placebo and lactulose in reducing the levels of benzodiazepine-like compounds in patients with liver cirrhosis: a pilot study.

Benzodiazepine-like compounds (BZDs), either taken with the diet or synthesized by intestinal bacterial flora, may represent a precipitating factor for hepatic encephalopathy (HE) in cirrhotic patients. We evaluated whether a diet and/or treatment with rifaximin or lactulose can reduce serum concentrations of BZDs in 18 cirrhotic patients without HE. Patients were given a standard diet for 7 days to keep the dietary intake of BZDs constant and were then randomized to a 7-day treatment with rifaximin 1,200 mg/day, lactulose 10-20 g three times daily, or placebo. Blood samples were collected at enrollment, at the end of the diet and drug treatment periods, and 7 days after the drug was stopped (follow-up). Serum concentrations of BZDs were measured by a radioligand binding technique after high-performance liquid chromatography extraction and purification and were expressed as diazepam equivalents (DE). No change in serum BZD concentrations was observed during the diet, while a statistically significant decrease from 105.6 +/- 66.5 to 63.5 +/- 49.5 pmol DE/ml was achieved in rifaximin-treated patients (p < 0.05) but not in patients treated with lactulose or placebo. During the followup, serum BZD concentrations returned to 104.5 +/- 74.0 pmol DE/ml in rifaximin-treated patients (p < 0.05 vs. end-treatment values), while no significant change was observed in the lactulose- and placebo-treated patients. These data indicate that control of bacterial flora with cyclic administration of rifaximin plays a pivotal role in avoiding increased plasma concentrations of BZDs, which represent a precipitating factor for HE inpatients with severe liver disease.