What is Rifaximin?
Rifaximin is a semisynthetic antibiotic based on rifamycin. It has poor oral bioavailability, meaning that very little of the drug will be absorbed into the blood stream when it is taken orally. Rifaximin is used in the treatment of traveler’s diarrhea and hepatic encephalopathy, for which it received orphan drug status from the U.S. Food and Drug Administration in 1998.
Mechanism of action?
Rifaximin interferes with transcription by binding to the β-subunit of bacterial RNA polymerase. This results in the blockage of the translocation step that normally follows the formation of the first phosphodiester bond, which occurs in the transcription process.
Why is this medication prescribed?
Generic Rifaximin 200mg / 400mg tablets are used to treat traveler’s diarrhea caused by certain bacteria in adults and children at least 12 years of age. Rifaximin 550mg tablets are used to prevent episodes of hepatic encephalopathy (changes in thinking, behavior, and personality caused by a build-up of toxins in the brain in people who have liver disease) in people at least 18 years of age who have liver disease. Rifaximin is in a class of medications called antibiotics. Rifaximin treats traveler’s diarrhea by stopping the growth of the bacteria that cause diarrhea. Rifaximin treats hepatic encephalopathy by stopping the growth of bacteria that produce toxins and that may worsen liver disease. Rifaximin will not work to treat diarrhea that is bloody or occurs with fever.
How should this medicine be used?
Rifaximin comes as a tablet to take by mouth with or without food. When rifaximin is used to treat traveler’s diarrhea, it is usually taken three times a day for 3 days. When rifaximin is used to prevent episodes of hepatic encephalopathy, it is usually taken twice a day. To help you remember to take rifaximin, take it around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take rifaximin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
If you are taking rifaximin to treat traveler’s diarrhea, your symptoms should improve within 24 to 48 hours after you start taking the medication. If your symptoms do not go away or they get worse, or if you develop a fever or bloody diarrhea, call your doctor.
Take rifaximin until you finish the prescription, even if you feel better. If you stop taking rifaximin to treat traveler’s diarrhea too soon, your infection may not be completely cured and the bacteria may become resistant to antibiotics. If you stop taking rifaximin to prevent hepatic encephalopathy, you may experience symptoms of encephalopathy.