XIFAXAN

What it is

XIFAXAN is a film-coated tablet containing 550 mg of rifaximin. Rifaximin is a non-aminoglycoside semi-synthetic, non-systemic antibiotic derived from rifamycin SV. Rifaximin acts by binding to the beta-subunit of bacterial DNA-dependent RNA polymerase resulting in inhibition of bacterial RNA synthesis. Due to the very low absorption from the gastro-intestinal tract rifaximin is locally acting in the intestinal lumen.

Approved indications

— Prevention of the recurrence of hepatic encephalopathy where other treatments have failed or are contraindicated.

Dosing overview

The recommended dose of XIFAXAN is one 550 mg tablet taken orally twice a day, with or without food.

Key safety warnings

Severe cutaneous adverse reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported in association with the use of rifaximin in patients with cirrhosis. Discontinue rifaximin at the first signs or symptoms of a severe cutaneous adverse reaction or other signs of hypersensitivity and conduct a clinical evaluation. Clostridium difficile-associated diarrhoea has been reported with use of nearly all antibacterial agents, including XIFAXAN, and may range in severity from mild diarrhoea to fatal colitis. CDAD must be considered in all patients who present with diarrhoea following antibiotic use. Both decreases and increases in international normalised ratio have been reported in patients maintained on warfarin and prescribed rifaximin. If co-administration is necessary, the international normalised ratio should be carefully monitored with the addition or withdrawal of rifaximin. Resistant strains of bacteria including Staphylococcus aureus are more likely to develop if patients are exposed to XIFAXAN long term. XIFAXAN is not recommended for use in patients at low risk for development of further episodes of HE or who have a satisfactory response to alternative treatments.

Contraindications

XIFAXAN is contraindicated in patients with a hypersensitivity to rifaximin, any of the rifamycin antimicrobial agents, or any of the components in XIFAXAN. Cases of intestinal obstruction.

PBS listing

XIFAXAN 550 mg tablets are listed on the PBS with one item number, authority required restriction, and an ex-manufacturer price of A$394.14.

Regulatory history

XIFAXAN rifaximin 550 mg tablets were first listed on the ARTG on 17 May 2012. In November 2014, the PBAC recommended XIFAXAN for the treatment of hepatic encephalopathy. In November 2016, the PBAC noted the report on the use of rifaximin and agreed that another utilisation review should be considered in 24 months' time.