Rifaximin


Generic Medicine Info
Indications and Dosage
Oral
Traveller's diarrhoea caused by non-invasive strains of E. coli
Adult: 200 mg tid for 3 days.
Child: ≥12 years Same as adult dose.

Oral
Hepatic encephalopathy
Adult: To reduce risk of overt hepatic encephalopathy recurrence: 550 mg bid.

Oral
Irritable bowel syndrome with diarrhoea
Adult: 550 mg tid for 14 days, retreat up to 2 times if symptoms recur.
Administration
Tablet: May be taken with or without food.
Contraindications
Hypersensitivity. Intestinal obstruction, diarrhoea with fever and/or blood in the stool, or diarrhoea caused by pathogens Campylobacter jejuni, Shigella spp., Salmonella spp.
Special Precautions
Patient with systemic bacterial infection. Severe hepatic impairment (Child-Pugh C). Children.
Adverse Reactions
Significant: Superinfection (e.g. C. difficile-associated diarrhoea).
Blood and lymphatic system disorders: Anaemia.
Cardiac disorders: Dyspnoea.
Gastrointestinal disorders: Nausea.
General disorders and administration site conditions: Fatigue, fever.
Metabolism and nutrition disorders: Peripheral oedema.
Musculoskeletal and connective tissue disorders: Muscle spasm.
Nervous system disorders: Dizziness, headache.
Psychiatric disorders: Depression.
Respiratory, thoracic and mediastinal disorders: Nasopharyngitis.
Skin and subcutaneous tissue disorders: Pruritus.
Vascular disorders: Epistaxis.
MonitoringParameters
Monitor temperature, blood in stool, changes in symptoms; changes in mental status in hepatic encephalopathy and signs of hypersensitivity.
Drug Interactions
Increased systemic exposure with ciclosporin (P-glycoprotein inhibitor). Decreased and increased INR with warfarin.
Action
Description: Rifaximin is a synthetic derivative of rifamycin which inhibits bacterial RNA synthesis by irreversibly binding to the β sub-unit of bacterial enzyme DNA-dependent RNA polymerase.
Pharmacokinetics:
Absorption: Nonabsorbed from the gastrointestinal tract. Bioavailability: <0.4%. Time to peak plasma concentration: Approx 1 hour.
Distribution: Plasma protein binding: 67.5% (healthy patients); 62% (patients with hepatic impairment).
Metabolism: Extensively metabolised in the liver and mainly by CYP3A4.
Excretion: Via faeces (96.6% as unchanged drug); urine (0.32% as metabolites). Elimination half-life: 5.6 hours.
Chemical Structure

Chemical Structure Image
Rifaximin

Source: National Center for Biotechnology Information. PubChem Database. Xifaxan, CID=6436173, https://pubchem.ncbi.nlm.nih.gov/compound/Xifaxan (accessed on Jan. 22, 2020)

Storage
Store between 20-25°C.
MIMS Class
ATC Classification
A07AA11 - rifaximin ; Belongs to the class of antibiotics. Used in the treatment of intestinal infections.
References
Anon. Rifaximin. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 19/11/2018.

Anon. Rifaximin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 19/11/2018.

Buckingham R (ed). Rifaximin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 19/11/2018.

Xifaxan (Valeant Pharmaceuticals North America LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 19/11/2018.

Disclaimer: This information is independently developed by MIMS based on Rifaximin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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