Faropenem, a highly efficacious and orally bioavailable beta-lactam antibiotic, exhibits an extensive range of in vitro antimicrobial activity against diverse gram-positive and -negative aerobes and anaerobes. Notably, Faropenem possesses inherent resistance to hydrolysis by virtually all beta-lactamases, including extended-spectrum beta-lactamases and AmpC beta-lactamases. Moreover, Faropenem has been developed as an oral prodrug, namely faropenem medoxomil, for the investigation of respiratory tract infections.

Faropenem is ineffective against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), Pseudomonas aeruginosa, and Stenotrophomonas maltophilia[1]. However, it effectively inhibits all isolates of B. anthracis, with MIC (Minimum Inhibitory Concentration) values ranging from ≤0.06 to >64 μg/liter and an MIC90 (the concentration at which 90% of isolates are inhibited) of 0.5 μg/ml. This MIC90 value for Faropenem is notably lower than those for other β-lactams, such as Meropenem (4 μg/ml), Amoxicillin-clavulanate (4 μg/ml), and Penicillin (8 μg/ml), demonstrating its superior efficacy against B. anthracis[2].

Faropenem, administered intraperitoneally (i.p.) at 24 hours post-challenge in 4-, 6-, and 12-hour intervals at dosages of 10, 20, 40, and 80 mg/kg/day for 14 days, demonstrates significant efficacy against B. anthracis in the murine post-exposure prophylaxis inhalation model[1].