Rifaximin is indicated for the following conditions:

• Treatment of traveler’s diarrhea caused by noninvasive strains of E. coli
• Reduction in the risk of overt hepatic encephalopathy
• Management of irritable bowel syndrome associated with bacterial overgrowth

Rifaximin is a semi-synthetic, rifamycin-derived, non-systemic antibiotic. Unlike many other orally administered antibiotics, only a very small amount of rifaximin is absorbed through the gastrointestinal tract into the systemic circulation. It acts by inhibiting bacterial RNA synthesis through binding to the beta-subunit of DNA-dependent RNA polymerase. Rifaximin has a broad spectrum of antibacterial activity and exerts bactericidal effects against many Gram-positive and Gram-negative, as well as aerobic and anaerobic bacteria.

• Traveler’s Diarrhea: For patients 12 years of age and older, the recommended dose is 200 mg three times daily for 3 days.
• Hepatic Encephalopathy: For patients 18 years of age and older, the recommended dose is 550 mg twice daily.
• Bacterial Overgrowth Associated with Irritable Bowel Syndrome: The recommended dose is 400 mg three times daily for 10 days or 550 mg three times daily for 14 days. Rifaximin may be taken with or without food.

An in vitro study suggests that rifaximin may induce CYP3A4. However, in patients with normal liver function, rifaximin is not expected to induce CYP3A4 when used at the recommended dosage regimen.

Rifaximin is contraindicated in patients with known hypersensitivity to rifaximin, any other rifamycin-class antimicrobial agent, or to any component of the formulation.

Reported side effects of rifaximin include flatulence, headache, abdominal pain, rectal tenesmus, urgency of defecation, nausea, constipation, fever, and vomiting. Serious hypersensitivity reactions have also been reported, including anaphylaxis, angioneurotic edema, and exfoliative dermatitis.

Rifaximin is classified as Pregnancy Category C. It is not known whether rifaximin is excreted in human breast milk.

Rifaximin is not effective in patients whose diarrhea is accompanied by fever and/or blood in the stool. Treatment with rifaximin should be discontinued if diarrhoeal symptoms worsen or persist for more than 24 to 48 hours, and alternative antibiotic therapy should be considered. As with nearly all antibacterial agents, pseudomembranous colitis has been reported with rifaximin and may range in severity from mild to life-threatening. Therefore, this diagnosis should be considered in patients who develop diarrhoea following the use of antibacterial agents.

Renal impairment: The pharmacokinetics of rifaximin in patients with impaired renal function have not been studied.

Hepatic impairment: Systemic exposure to rifaximin was found to be significantly increased in patients with hepatic impairment compared with healthy individuals.

There is no specific information available regarding the treatment of rifaximin overdose. In the event of an overdose, rifaximin should be discontinued, and the patient should be managed with symptomatic treatment and appropriate supportive measures as needed.

4-Quinolone preparations

Store below 30°C, protected from light and moisture. Keep out of the reach of children.