Description

Simple

An antibiotic used to treat various bacterial infections in the stomach and liver, including traveler's diarrhea and irritable bowel syndrome.

Clinical

A rifamycin-based non-systemic antibiotic used for the treatment of gastrointestinal bacterial infections, such as traveler's diarrhea and irritable bowel syndrome, and reduction of overt hepatic encephalopathy recurrence in adults.

Overview

Rifaximin is a semisynthetic, rifamycin-based non-systemic antibiotic, meaning that the drug will not pass the gastrointestinal wall into the circulation as is common for other types of orally administered antibiotics. It has multiple indications and is used in treatment of traveller's diarrhea caused by E. coli; reduction in risk of overt hepatic encephalopathy recurrence; as well as diarrhea-predominant irritable bowel syndrome (IBS-D) in adult women and men. It is marketed under the brand name Xifaxan by Salix Pharmaceuticals.

Pharmacology

Indication

Rifaximin has multiple indications by the FDA: for the treatment of patients (≥12 years of age) with traveller's diarrhea caused by noninvasive strains of Escherichia coli; for the reduction of overt hepatic encephalopathy recurrence in patients ≥18 years of age; and in May 2015 it was approved for... Read more

Pharmacodynamic

Rifaximin is a structural analog of rifampin and a non-systemic, gastrointestinal site-specific antibiotic. This non-systemic property of the drug is due to the addition of a pyridoimidazole ring, which renders it non-absorbable. Rifaximin acts by inhibiting bacterial ribonucleic acid (RNA) synthesi... Read more

Mechanism of action

Rifaximin acts by inhibiting RNA synthesis in susceptible bacteria by binding to the beta-subunit of bacterial deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase enzyme. This binding blocks translocation, which stops transcription.

Absorption

Low absorption in both the fasting state and when administered within 30 minutes of a high-fat breakfast.

Protein binding

Information currently not available.

Volume of distribution

Information currently not available.

Clearance

Information currently not available.

Half life

Approximately 6 hours.

Route of elimination

In a mass balance study, after administration of 400 mg 14C-rifaximin orally to healthy volunteers, of the 96.94% total recovery, 96.62% of the administered radioactivity was recovered in feces almost exclusively as the unchanged drug and 0.32% was recovered in urine mostly as metabolites with 0.03%... Read more

Toxicity

LD50 > 2 g/kg (orally, in rats)

Adverse Effects

Contraindications

Information currently not available.

Food Interactions

    Information currently not available.

Interactions

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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The metabolism of (R)-warfarin can be increased when combined with Rifaximin.
(S)-Warfarin
The metabolism of (S)-Warfarin can be increased when combined with Rifaximin.
4-hydroxycoumarin
The metabolism of 4-hydroxycoumarin can be increased when combined with Rifaximin.
9-aminocamptothecin
The metabolism of 9-aminocamptothecin can be increased when combined with Rifaximin.
Abiraterone
The metabolism of Abiraterone can be increased when combined with Rifaximin.
Acebutolol
The metabolism of Acebutolol can be increased when combined with Rifaximin.
Acenocoumarol
The metabolism of Acenocoumarol can be increased when combined with Rifaximin.
Afatinib
The serum concentration of Rifaximin can be increased when it is combined with Afatinib.
Albendazole
The metabolism of Albendazole can be increased when combined with Rifaximin.
Alfentanil
The metabolism of Alfentanil can be increased when combined with Rifaximin.
Allylestrenol
The metabolism of Allylestrenol can be increased when combined with Rifaximin.
Almotriptan
The metabolism of Almotriptan can be increased when combined with Rifaximin.
Alpelisib
The metabolism of Alpelisib can be increased when combined with Rifaximin.
Alprazolam
The metabolism of Alprazolam can be increased when combined with Rifaximin.
Alprenolol
The metabolism of Alprenolol can be increased when combined with Rifaximin.
Aminophenazone
The metabolism of Aminophenazone can be increased when combined with Rifaximin.
Aminophylline
The metabolism of Aminophylline can be increased when combined with Rifaximin.
Amiodarone
The serum concentration of Rifaximin can be increased when it is combined with Amiodarone.
Amitriptyline
The metabolism of Amitriptyline can be increased when combined with Rifaximin.
Amlodipine
The metabolism of Amlodipine can be increased when combined with Rifaximin.
16 References
  1. 1 . Cottreau J, Baker SF, DuPont HL, Garey KW: Rifaximin: a nonsystemic rifamycin antibiotic for gastrointestinal infections. Expert Rev Anti Infect Ther. 2010 Jul;8(7):747-60. doi: 10.1586/eri.10.58.PubMed: 20586560
  2. 2 . Williams R, Bass N: Rifaximin, a nonabsorbed oral antibiotic, in the treatment of hepatic encephalopathy: antimicrobial activity, efficacy, and safety. Rev Gastroenterol Disord. 2005;5 Suppl 1:S10-8.PubMed: 15976747
  3. 3 . Koo HL, DuPont HL: Rifaximin: a unique gastrointestinal-selective antibiotic for enteric diseases. Curr Opin Gastroenterol. 2010 Jan;26(1):17-25. doi: 10.1097/MOG.0b013e328333dc8d.PubMed: 19881343
  4. 4 . Pakyz AL: Rifaximin: a new treatment for travelers' diarrhea. Ann Pharmacother. 2005 Feb;39(2):284-9. Epub 2004 Dec 14.PubMed: 15598963
  5. 5 . Jalan R: Rifaximin in hepatic encephalopathy: more than just a non-absorbable antibiotic? J Hepatol. 2010 Sep;53(3):580-2. doi: 10.1016/j.jhep.2010.05.002. Epub 2010 May 31.PubMed: 20561708
  6. 6 . Lawrence KR, Klee JA: Rifaximin for the treatment of hepatic encephalopathy. Pharmacotherapy. 2008 Aug;28(8):1019-32. doi: 10.1592/phco.28.8.1019.PubMed: 18657018
  7. 7 . Layer P, Andresen V: Review article: rifaximin, a minimally absorbed oral antibacterial, for the treatment of travellers' diarrhoea. Aliment Pharmacol Ther. 2010 Jun;31(11):1155-64. doi: 10.1111/j.1365-2036.2010.04296.x. Epub 2010 Mar 11.PubMed: 20331580
  8. 8 . Ojetti V, Lauritano EC, Barbaro F, Migneco A, Ainora ME, Fontana L, Gabrielli M, Gasbarrini A: Rifaximin pharmacology and clinical implications. Expert Opin Drug Metab Toxicol. 2009 Jun;5(6):675-82. doi: 10.1517/17425250902973695.PubMed: 19442033
  9. 9 . Scarpignato C, Pelosini I: Rifaximin, a poorly absorbed antibiotic: pharmacology and clinical potential. Chemotherapy. 2005;51 Suppl 1:36-66.PubMed: 15855748
  10. 10 . Gillis JC, Brogden RN: Rifaximin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic potential in conditions mediated by gastrointestinal bacteria. Drugs. 1995 Mar;49(3):467-84.PubMed: 7774516
  11. 11 . Koo HL, Dupont HL, Huang DB: The role of rifaximin in the treatment and chemoprophylaxis of travelers' diarrhea. Ther Clin Risk Manag. 2009;5:841-8. Epub 2009 Nov 2.PubMed: 19898648
  12. 12 . DuPont HL: Systematic review: prevention of travellers' diarrhoea. Aliment Pharmacol Ther. 2008 May;27(9):741-51. doi: 10.1111/j.1365-2036.2008.03647.x. Epub 2008 Feb 14.PubMed: 18284650
  13. 13 . Romero-Gomez M: Pharmacotherapy of hepatic encephalopathy in cirrhosis. Expert Opin Pharmacother. 2010 Jun;11(8):1317-27. doi: 10.1517/14656561003724721.PubMed: 20384539
  14. 14 . Scarpignato C, Pelosini I: Experimental and clinical pharmacology of rifaximin, a gastrointestinal selective antibiotic. Digestion. 2006;73 Suppl 1:13-27. Epub 2006 Feb 8.PubMed: 16498249
  15. 15 . Pimentel M: Review of rifaximin as treatment for SIBO and IBS. Expert Opin Investig Drugs. 2009 Mar;18(3):349-58. doi: 10.1517/13543780902780175 .PubMed: 19243285
  16. 16 . Rifaximin Australian Public Assessment Report File