This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cirrhosis, Subject name: Medicine
Antibiotic of choice in cirrhotic patient to prevent encephalopathy: 
Select and explain. 
A. Neomycin, B. Ampicillin, C. Metronidazole, D. Rifaximin
D: Rifaximin
Answer: D: Rifaximin 
Explanation: Treatment of hepatic encephalopathy 1. Correct precipitating factors 2. Use lactulose- results in colonic acidification. 2. Poorly absorbed antibiotics- neomycin and metronidazole. More recently, rifaximin at 550 mg twice daily has been very effective in treating encephalopathy without the known side effects of neomycin or metronidazole.