From the Guidelines
Rifaximin is a nonabsorbable antibiotic that belongs to the rifamycin class of antibiotics, primarily acting in the gastrointestinal tract to treat conditions such as traveler's diarrhea, irritable bowel syndrome with diarrhea (IBS-D), and hepatic encephalopathy. This classification is based on the most recent and highest quality evidence available, including a study published in the Journal of Travel Medicine in 2017 1, which discusses the use of rifaximin in the treatment of traveler's diarrhea. The mechanism of action of rifaximin involves inhibiting bacterial RNA synthesis, effectively stopping bacterial growth, and its poor absorption in the intestines allows it to concentrate in the gut and target intestinal bacteria without significant systemic effects 2. Some key points to consider when using rifaximin include:
- It is typically prescribed as 550 mg tablets taken orally three times daily for 10-14 days, though dosing may vary based on the specific condition being treated.
- Rifaximin has been shown to be effective in treating non-invasive traveler's diarrhea, but its efficacy in treating invasive pathogens is limited 1.
- The safety profile of rifaximin is excellent, with a low risk of adverse effects, and it has been demonstrated to alter the microbiome in a potentially beneficial way 3.
- Patients should be aware that rifaximin may cause nausea, bloating, or headache in some cases, and it is essential to complete the full course of treatment as prescribed, even if symptoms improve before finishing the medication. Overall, rifaximin is a valuable treatment option for certain gastrointestinal conditions, and its use should be guided by the most recent and highest quality evidence available.
From the FDA Drug Label
XIFAXAN tablets contain rifaximin, a non-aminoglycoside semi-synthetic, nonsystemic antibiotic derived from rifamycin SV. Rifaximin is a structural analog of rifampin Rifaximin (Xifaxan) is a non-aminoglycoside semi-synthetic, nonsystemic antibiotic derived from rifamycin SV and is a structural analog of rifampin 4.
- It belongs to the rifamycin class of antibiotics.
- The antibiotic is nonsystemic, meaning it acts locally in the gut and is not absorbed into the bloodstream in significant amounts.
From the Research
Overview of Rifaximin
- Rifaximin is a gastrointestinal-selective antibiotic with a broad spectrum of antimicrobial activity 5
- It has an excellent safety profile, minimal drug interactions, and negligible impact on the intestinal microbiome 5
- Rifaximin is effective against Gram-positive, Gram-negative, and anaerobic bacteria 6, 7, 8
Mechanism of Action
- Rifaximin acts by inhibiting bacterial ribonucleic acid (RNA) synthesis 7
- It inhibits RNA polymerase of most bacterial genera 9
Pharmacokinetic Properties
- Rifaximin is poorly absorbed after oral administration, with less than 1% of the drug being absorbed 6, 8
- It achieves high local concentrations in the gastrointestinal tract, making it effective for treating gastrointestinal disorders 6, 8
Therapeutic Potential
- Rifaximin is used to treat various gastrointestinal disorders, including travelers' diarrhea, hepatic encephalopathy, irritable bowel syndrome, and small bowel intestinal overgrowth 5, 6, 9, 7, 8
- It has potential uses in treating other conditions, such as inflammatory bowel disease, colonic diverticular disease, and Clostridium difficile infection 5, 7, 8