Brands, Medical Use, Clinical Data
- Anti-Infective Agents
- Gastrointestinal Agents
Brands / Synonyms
Fatroximin; Normix; Rifacol; Rifamixin; Rifamycin L 105; Rifamycin L 105SV; Rifaxidin; Rifaximin [USAN:INN]; Rifaximina [Spanish]; Rifaximine [French]; Rifaximinum [Latin]; Ritacol; Xifaxan; Xifaxan
For the treatment of patients (>=12 years of age) with travelers' diarrhea caused by noninvasive strains of Escherichia coli.
Rifaximin is a structural analog of rifampin and non-systemic, gastrointestinal site-specific antibiotic. Rifaximin acts by inhibiting bacterial ribonucleic acid (RNA) synthesis. While an increase in pulmonary hydrogen excretion is evident in diverticular disease, the therapeutic effect of rifaximin does not appear to be due to a persistent correction of this alteration and the drug appears to cause no significant imbalance in the intestinal ecosystem.
Mechanism of Action
Rifaximin is a product of synthesis of rifamycin, an antibiotic with low gastrointestinal absorption and good antibacterial activity (Marchi et al, 1985). It acts on the beta-subunit of the deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase enzyme of microorganisms to inhibit RNA synthesis.
Low absorption in both the fasting state and when administered within 30 minutes of a high-fat breakfast.
LD50 > 2 g/kg (orally, in rats)
Biotrnasformation / Drug Metabolism
XIFAXAN™ Tablets are contraindicated in patients with a hypersensitivity to rifaximin, any of
the rifamycin antimicrobial agents, or any of the components in XIFAXAN™ Tablets.
Although in vitro studies demonstrated the potential of rifaximin to interact with cytochrome
P450 3A4 (CYP3A4), a clinical drug-drug interaction study demonstrated that rifaximin did not significantly affect
the pharmacokinetics of midazolam either presystemically or systemically. An additional clinical drug-drug
interaction study showed no effect of rifaximin on the presystemic metabolism of an oral contraceptive containing
ethinyl estradiol and norgestimate. Therefore, clinical interactions with drugs metabolized by human cytochrome P450
isoenzymes are not expected.