Rifaximin

**Semantic type:** Antibiotic|Pharmacologic Substance

**Definition:** An orally administered, semi-synthetic, nonsystemic antibiotic derived from rifamycin SV with antibacterial activity. Rifaximin binds to the beta-subunit of bacterial DNA-dependent RNA polymerase, inhibiting bacterial RNA synthesis and bacterial cell growth. As rifaximin is not well absorbed, its antibacterial activity is largely localized to the gastrointestinal tract.

**Synonyms:** - RIFAXIMIN - Xifaxan