Carbenicillin is a bactericidal antibiotic which belongs to the group of the penicillins. It destroy gram-negative bacteria such as Pseudomonas aeruginosa by preventing bacterial cell wall synthesis, inhibiting crosslinking of peptidoglycan by binding and inactivating transpeptidases. The carboxypenicillins are susceptible to degradation by beta-lactamase enzymes, although they are more resistant than ampicillin to degradation. Carbenicillin is also more stable at lower pH than ampicillin.
Carbenicillin is effective in the treatment of infections caused by certain susceptible strains of Gram-negative bacteria, such as Pseudomonas and Proteus.