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Rifaximin ball-and-stick.png
Clinical data
Trade names Xifaxan, Xifaxanta, Normix, other
AHFS/Drugs.com Monograph
MedlinePlus a604027
  • US: C (Risk not ruled out)
Routes of
by mouth
ATC code
Legal status
Legal status
  • In general: ℞ (Prescription only)
Pharmacokinetic data
Bioavailability < 0.4%
Metabolism Hepatic
Biological half-life 6 hours
Excretion Fecal (97%)
CAS Number
PubChem CID
ECHA InfoCard 100.111.624
Chemical and physical data
Formula C43H51N3O11
Molar mass 785.879 g/mol
3D model (JSmol)
 NYesY (what is this?)  (verify)

Rifaximin, sold under the trade name Xifaxan among others, is an antibiotic used to treat traveler's diarrhea, irritable bowel syndrome, and hepatic encephalopathy.[1] It has poor absorption when taken by mouth.

It is based on rifamycin. Rifaximin was approved for medical use in the United States in 2004.[1] In the United States it costs 62.13 USD per day for 1100 mg of rifaximin (1,864.00 USD per month) as of January 2017.[2] In Russia as of 2016 a similar dose costs 231.25 RUB (approximately 4 USD).[3]

Medical uses[edit]

Rifaximin may be used to treat and prevent traveler's diarrhea.[4][5]

Irritable bowel syndrome[edit]

It may be efficacious in relieving chronic functional symptoms of bloating and flatulence that are common in irritable bowel syndrome (IBS),[6]

C. difficile infection[edit]

Rifaximin may also be a useful addition to vancomycin when treating patients with relapsing C. difficile infection.[7][8] Although exposure to rifamycins in the past may increase risk for resistance, so rifaximin should be avoided in such cases.

Hepatic encephalopathy[edit]

In the United States, rifaximin has orphan drug status for the treatment of hepatic encephalopathy.[9] Although high-quality evidence is still lacking, rifaximin appears to be as effective as or more effective than other available treatments for hepatic encephalopathy (such as lactulose), is better tolerated, and may work faster.[10] Rifaximin is taken by mouth. It has minimal side effects, prevents reoccurring encephalopathy, and is associated with high patient satisfaction. Patients are more compliant and satisfied to take this medication than any other due to minimal side effects, prolong remission, and overall cost.[11] The drawbacks to rifaximin are increased cost and lack of robust clinical trials for HE without combination lactulose therapy.

Mechanism of action[edit]

Rifaximin interferes with transcription by binding to the β-subunit of bacterial RNA polymerase.[12] 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.[13]


In the United States, Salix Pharmaceuticals holds a US Patent for rifaximin and markets the drug under the name Xifaxan.[14][15] In addition to receiving FDA approval for traveler’s diarrhea and (marketing approved for)[15] hepatic encephalopathy, rifaximin received FDA approval for IBS in May 2015.[16] No generic formulation is available in the US and none has appeared due to the fact that the FDA approval process was ongoing. If rifaximin receives full FDA approval for hepatic encephalopathy it is likely that Salix will maintain marketing exclusivity and be protected from generic formulations until March 24, 2017.[15]

Rifaximin is approved in 33 countries for GI disorders.[17][18] On August 13, 2013, Health Canada issued a Notice of Compliance to Salix Pharmaceuticals Inc. for the drug product Zaxine.[19] In India it is available under the brand names Ciboz and Xifapill.[citation needed] In Russia and Ukraine the drug is sold under the name Alfa Normix (Альфа Нормикс), produced by Alfa Wassermann S.p.A (Italy).[20]


  1. ^ a b "Rifaximin". The American Society of Health-System Pharmacists. Retrieved 8 January 2017. 
  2. ^ "NADAC as of 2017-01-25 | Data.Medicaid.gov". Centers for Medicare and Medicaid Services. Retrieved 25 January 2017. 
  3. ^ "Drug prices archive of the administration of the city of Krasnodar (in Russian)". 
  4. ^ "Xifaxan label information" (PDF).  Retrieved November 15, 2008.
  5. ^ DuPont, H (2007). "Therapy for and Prevention of Traveler's Diarrhea". Clinical Infectious Diseases. 45 (45 (Suppl 1)): S78–S84. PMID 17582576. doi:10.1086/518155. 
  6. ^ Sharara A, Aoun E, Abdul-Baki H, Mounzer R, Sidani S, ElHajj I (2006). "A randomized double-blind placebo-controlled trial of rifaximin in patients with abdominal bloating and flatulence". Am J Gastroenterol. 101 (2): 326–33. PMID 16454838. doi:10.1111/j.1572-0241.2006.00458.x. 
  7. ^ Johnson S, Schriever C, Galang M, et al. Interruption of recurrent Clostridium difficile-associated diarrhea episodes by serial therapy with vancomycin and rifaximin. Clin Infect Dis 2007; 44:846.
  8. ^ Garey KW, Ghantoji SS, Shah DN, et al. A randomized, double-blind, placebo-controlled pilot study to assess the ability of rifaximin to prevent recurrent diarrhoea in patients with Clostridium difficile infection. J Antimicrob Chemother 2011; 66:2850.
  9. ^ Wolf, David C. (2007-01-09). "Hepatic Encephalopathy". eMedicine. WebMD. Retrieved 2007-02-15. 
  10. ^ Lawrence KR, Klee JA (2008). "Rifaximin for the treatment of hepatic encephalopathy". Pharmacotherapy. 28 (8): 1019–32. PMID 18657018. doi:10.1592/phco.28.8.1019.  Free full text with registration at Medscape.
  11. ^ Kimer, Nina; Krag, Aleksander; Gluud, Lise L. (March 2014). "Safety, efficacy, and patient acceptability of Rifaximin for hepatic encephalopathy". Patient Preference and Adherence. 8: 331–338. PMC 3964161Freely accessible. PMID 24672227. doi:10.2147/PPA.S41565. 
  12. ^ PharmD, Benjamin Barner,; PharmD, Brett Feret, (1 July 2010). "Rifaximin: A nonabsorbable, broad-spectrum antibiotic for reduction in the risk for recurrence of overt hepatic encephalopathy". 
  13. ^ DrugBank, ed. (22 March 2017). "Rifaximin" – via DrugBank.ca. 
  14. ^ "XIFAXAN (Rifaximin) 550 mg - Reduce Overt Hepatic Encephalopathy Recurrences". 
  15. ^ a b c http://www.accessdata.fda.gov/scripts/cder/ob/docs/obdetail.cfm?Appl_No=022554&TABLE1=OB_Rx
  16. ^ "Press Announcements - FDA approves two therapies to treat IBS-D". 
  17. ^ http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/GastrointestinalDrugsAdvisoryCommittee/UCM203248.pdf
  18. ^ "Pharmaceutical News & Media - Salix Pharmaceuticals". 
  19. ^ Diseases, Government of Canada, Health Canada, Health Products and Food Branch, Therapeutic Products Directorate, Bureau of Gastroenterology Infection and Viral. "Summary Basis of Decision (SBD): Zaxine - 2013 - Health Canada". 
  20. ^ "Alfa Normix - Russian medical server". 

External links[edit]