Medically reviewed on August 12, 2018
(rif AX i min)
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Xifaxan: 200 mg [contains edetate disodium]
Xifaxan: 550 mg
Brand Names: U.S.
- Antibiotic, Miscellaneous
Rifaximin inhibits bacterial RNA synthesis by binding to bacterial DNA-dependent RNA polymerase.
Traveler's diarrhea: Low
Hepatic encephalopathy: Increased absorption in patients with Child-Pugh class C compared with patients with Child-Pugh class A
Extensive, mainly by CYP3A
Feces (96.6% primarily as unchanged drug); urine (0.32%)
Time to Peak
Healthy subjects and ISB-D patients: ~1 hour
Healthy subjects: 5.6 hours; IBS-D patients: 6 hours
Healthy subjects: 67.5%; Hepatic impairment: 62%
Special Populations: Hepatic Function Impairment
The mean AUC in patients with hepatic impairment of Child-Pugh class A, B, and C was 10-, 14-, and 21-fold higher, respectively, compared with that of healthy subjects.
Use: Labeled Indications
Hepatic encephalopathy: Reduction in the risk of overt hepatic encephalopathy recurrence in adults
Irritable bowel syndrome with diarrhea: Treatment of irritable bowel syndrome with diarrhea (IBS-D) in adults
Traveler's diarrhea: Treatment of traveler's diarrhea caused by noninvasive strains of E. coli in adults and pediatric patients ≥12 years of age
Limitations of use: Rifaximin should not be used in patients with diarrhea complicated by fever or blood in the stool or diarrhea caused by pathogens other than E. coli.
Off Label Uses
Clostridium difficile infection (second or subsequent recurrence)
Based on the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) guidelines for Clostridium difficile infection in adults and children, rifaximin, following a standard course of oral vancomycin therapy, is an adjunctive treatment option in patients with >1 recurrence of C. difficile infection.
Overt hepatic encephalopathy episodes (treatment)
Based on the American Association for the Study of Liver Diseases (AASLD) practice guideline for hepatic encephalopathy, rifaximin may be added to lactulose therapy for the treatment of episodes of overt hepatic encephalopathy.
Hypersensitivity to rifaximin, other rifamycin antibiotics, or any component of the formulation
Clostridium difficile infection (second or subsequent recurrence) (off-label use): Oral: 400 mg 3 times daily for 20 days; administer after a standard course of oral vancomycin (IDSA/SHEA [McDonald 2018])
Hepatic encephalopathy: Oral:
Reduction of overt hepatic encephalopathy recurrence: 550 mg 2 times daily. Note: Supporting clinical trial evaluated efficacy over 6-month treatment period.
Treatment of hepatic encephalopathy (off-label use): 400 mg every 8 hours for 5 to 10 days (Mas 2003)
Irritable bowel syndrome with diarrhea (IBS-D): Oral: 550 mg 3 times daily for 14 days; may be retreated up to 2 times with the same dosing regimen if symptoms recur.
Traveler's diarrhea: Oral: 200 mg 3 times daily for 3 days
Refer to adult dosing.
Traveler's diarrhea: Oral: Children ≥12 years and Adolescents: Refer to adult dosing.
Dosing: Renal Impairment
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied).
Dosing: Hepatic Impairment
No dosage adjustment necessary. Use with caution in severe impairment (Child-Pugh class C); however, systemic absorption is limited and pharmacokinetic parameters are highly variable.
A 20 mg/mL oral suspension may be made using tablets. Crush six 200 mg tablets and reduce to a fine powder. Add 30 mL of a 1:1 mixture of Ora-Sweet® and Ora-Plus® or a 1:1 mixture of Ora-Sweet® SF and Ora-Plus®; mix well while adding the vehicle in geometric proportions to almost 60 mL; transfer to a calibrated bottle, rinse mortar with vehicle, and add quantity of vehicle sufficient to make 60 mL. Label "shake well". Stable 60 days at room temperature.Cober MP, Johnson CE, Lee J, et al, "Stability of Extemporaneously Prepared Rifaximin Oral Suspensions," Am J Health Syst Pharm, 2010, 67(4):287-89.20133533
Oral: Administer with or without food.
Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).
BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Avoid combination
BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Monitor therapy
CycloSPORINE (Systemic): May increase the serum concentration of RifAXIMin. Monitor therapy
Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Monitor therapy
P-glycoprotein/ABCB1 Inhibitors: May increase the serum concentration of RifAXIMin. Monitor therapy
Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Consider therapy modification
Frequency of adverse events generally higher following treatment for hepatic encephalopathy (HE). Percentages are presented for HE unless otherwise stated.
Cardiovascular: Peripheral edema (15%)
Central nervous system: Dizziness (13%), fatigue (12%)
Hepatic: Ascites (11%)
Gastrointestinal: Nausea (14%; irritable bowel syndrome with diarrhea 2% to 3%)
2% to 10%:
Central nervous system: Headache (travelers' diarrhea 10%), depression (7%)
Dermatological: Pruritus (9%), skin rash (5%)
Gastrointestinal: Abdominal pain (>2% to 9%), pseudomembranous colitis (<5%; travelers' diarrhea or irritable bowel syndrome with diarrhea <2%)
Hematologic & oncologic: Anemia (8%)
Hepatic: Increased serum ALT (irritable bowel syndrome with diarrhea 2%)
Neuromuscular & skeletal: Muscle spasm (9%), arthralgia (6%), increased creatine phosphokinase (<5%; travelers' diarrhea or irritable bowel syndrome with diarrhea <2%)
Respiratory: Nasopharyngitis (7%), dyspnea (6%), epistaxis (>2% to 5%)
Miscellaneous: Fever (6%)
All indications: <2%, postmarketing, and/or case reports: Anaphylaxis, angioedema, Clostridium difficile associated diarrhea, exfoliative dermatitis, flushing, hypersensitivity reaction, urticaria
Concerns related to adverse effects:
• Hypersensitivity: Hypersensitivity reactions (eg, exfoliative dermatitis, rash, urticaria, flushing, angioneurotic edema, pruritus, anaphylaxis) have occurred; these events have occurred as early as within 15 minutes of drug administration.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.
• Diarrhea: Appropriate use: Avoid use in diarrhea with fever and/or blood in the stool and in the treatment of diarrhea due to pathogens other than E. coli, including C. jejuni, Shigella, and Salmonella (efficacy has not been established). Consider alternative therapy if symptoms persist or worsen after 24 to 48 hours of treatment.
• Hepatic impairment: Efficacy for prevention of encephalopathy has not been established in patients with a Model for End-Stage Liver Disease (MELD) score >25; use caution in patients with severe hepatic impairment (Child-Pugh class C).
Concurrent drug therapy issues:
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
Dosage form specific issues:
• Propylene glycol: Some dosage forms may contain propylene glycol; large amounts are potentially toxic and have been associated hyperosmolality, lactic acidosis, seizures, and respiratory depression; use caution (AAP 1997; Zar 2007).
• Appropriate use: Not for treatment of systemic infections; <1% is absorbed orally.
Hypersensitivity reactions, temperature, blood in stool, change in symptoms; monitor changes in mental status in hepatic encephalopathy
Adverse events have been observed in some animal reproduction studies. Due to the limited oral absorption of rifaximin in patients with normal hepatic function, exposure to the fetus is expected to be low.
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience rhinitis, pharyngitis, muscle spasm, joint pain, headache, dizziness, abdominal pain, or nausea. Have patient report immediately to prescriber swelling of arms or legs, abdominal edema, severe loss of strength and energy, shortness of breath, depression, or signs of Clostridium difficile (C. diff)-associated diarrhea (abdominal pain or cramps, severe diarrhea or watery stools, or bloody stools) (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
More about rifaximin
- Rifaximin Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- Support Group
- En Español
- 71 Reviews
- Drug class: miscellaneous antibiotics
Other brands: Xifaxan