Active ingredient: Rifaximin - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

• Anti-Infective Agents
• Gastrointestinal Agents

Dosage Forms

• Not Available

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

Indications

For the treatment of patients (>=12 years of age) with travelers' diarrhea caused by noninvasive strains of Escherichia coli.

Pharmacology

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.

Absorption

Low absorption in both the fasting state and when administered within 30 minutes of a high-fat breakfast.

Toxicity

LD₅₀ > 2 g/kg (orally, in rats)

Biotrnasformation / Drug Metabolism

Not Available

Contraindications

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.

Drug Interactions

Drug-Drug Interactions

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.