Laxatives

A patient with liver cirrhosis and history of hepatic encephalopathy is started on a regimen of rifaximin and lactulose. The physician educates the patient on the rationale of these medications for managing hepatic encephalopathy. When discussing the reason for taking rifaximin, which of the following statements by the physician is most appropriate?

1: This medication promotes bowel regularity
2: This medication treats a bacterial infection in the liver
3: This medication eradicates ammonia-producing gastrointestinal bacteria
4: This medication binds to and clears ammonia from the gastrointestinal tract