Fidaxomicin

FIDAXOMICIN

Fidaxomicin is a narrow-spectrum, macrocyclic antibiotic that isactive against gram-positive aerobes and anaerobes but lacks activity against gram-negative bacteria. Fidaxomicin inhibits bac-terial protein synthesis by binding to the sigma subunit of RNA polymerase. When administered orally, systemic absorption is negligible but fecal concentrations are high. Fidaxomicin has been approved by the FDA for the treatment for C difficile colitis in adults. Preliminary data have demonstrated it is as effective as oral vancomycin and may be associated with lower rates of relapsing disease. The FDA has granted orphan drug designation to all for-mulations of fidaxomicin for the treatment of C difficile infection in pediatric patients aged 16 years and younger. Fidaxomicin is administered as 200 mg orally twice daily.