Antibacterial Spectrum: Cefpodoxime proxetil, after being hydrolyzed by nonspecific esterases in vivo to cefpodoxime, exerts antibacterial activity against both Gram-positive and Gram-negative bacteria.
Mechanism of Action: Cefpodoxime proxetil inhibits the biosynthesis of microbial cell walls, leading to bactericidal activity. Specifically, it binds to four sites on specific penicillin-binding proteins, inhibiting bacterial cell wall peptidoglycan synthetase (including transpeptidase, carboxypeptidase, and endopeptidase), thereby impeding the synthesis of cell wall peptidoglycan, causing cell wall defects, bacterial swelling, deformation, and lysis.
β-Lactamase Stability: Cefpodoxime proxetil is stable to β-lactamases, so many β-lactamase-producing microorganisms resistant to penicillin and cephalosporins remain sensitive to this product, but it is ineffective against some extended-spectrum β-lactamases.
III. Drug Interactions
When combined with antacids (such as aluminum hydroxide) or H2 receptor antagonists (such as ranitidine), Cefpodoxime proxetil's plasma concentration and drug absorption may be reduced due to neutralization of gastric acid.
Coadministration with drugs that increase gastric pH can result in significant decreases in Cmax and AUC values, while coadministration with drugs that decrease gastric pH can increase cefpodoxime absorption.
Acetylcysteine can disrupt the β-lactam ring, affecting cephalosporin absorption and reducing cephalosporin bioavailability, but it has no significant effect on the bioavailability of Cefpodoxime proxetil.
