Xifaxan (rifaximin)

The following drug information is obtained from various newswires, published medical journal articles, and medical conference presentations.

Approval Status:

Approved March 2010

Specific Treatments:

hepatic encephalopathy

Therapeutic Areas

General Information

Xifaxan contains rifaximin, a non-aminoglycoside semi-synthetic, nonsystemic antibiotic derived from rifamycin. Rifaximin exerts its antimicrobial effect by inhibiting bacterial RNA synthesis.

Xifaxan is specifically indicated for reduction in risk of overt hepatic encephalopathy recurrence in adults.

Xifaxan is supplied as 550 mg tablet for oral administration. The recommended dose is one 550 mg tablet taken orally two times a day, with or without food.

Clinical Results

FDA Approval
The FDA approval of Xiaxan for hepatic encephalopathy was based on a randomized, placebo-controlled, double-blind, multi-center 6-month trial in adults across the U.S., Canada and Russia. All subjects were defined as being in remission from hepatic encephalopathy and had at least 2 episodes of HE associated with chronic liver disease in the previous 6 months. A total of 299 subjects were randomized to receive either Xifaxan or placebo. The primary endpoint was the time to first breakthrough overt HE episode. A breakthrough overt HE episode was defined as a marked deterioration in neurological function and an increase of Conn score to Grade >2. Breakthrough overt HE episodes were experienced by 31 of 140 subjects (22%) in the Xifaxan group and by 73 of 159 subjects (46%) in the placebo group during the 6 month treatment period. Comparison of Kaplan-Meier estimates of event-free curves showed Xifaxan significantly reduced the risk of HE breakthrough by 58% during the 6-month treatment period.

Side Effects

Adverse events associated with the use of Xifaxan may include, but are not limited to, the following:

  • peripheral edema
  • nausea
  • dizziness
  • fatigue
  • ascites
  • flatulence
  • headache

Mechanism of Action

Xifaxan contains rifaximin, a non-aminoglycoside semi-synthetic, nonsystemic antibiotic derived from rifamycin. Rifaximin acts by binding to the beta-subunit of bacterial DNA-dependent 507 RNA polymerase resulting in inhibition of bacterial RNA synthesis.

Literature References

Bass NM, Mullen KD, Sanyal A, Poordad F, Neff G, Leevy CB, Sigal S, Sheikh MY, Beavers K, Frederick T, Teperman L, Hillebrand D, Huang S, Merchant K, Shaw A, Bortey E, Forbes WP Rifaximin treatment in hepatic encephalopathy The New England Journal of Medicine 2010 Mar 25;362(12):1071-81

Additional Information

For additional information regarding Xifaxan or hepatic encephalopathy, please visit the Xifaxan web page.