Phenoxymethyl Penicillin inhibits the final cross-linking stage of peptidoglycan production through binding and inactivation of transpeptidases on the inner surface of the bacterial cell membrane, thus inhibiting bacterial cell wall synthesis.
By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, Phenoxymethyl Penicillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that Phenoxymethyl Penicillin interferes with an autolysin inhibitor.
It may be less active against some susceptible organisms, particularly gm-ve bacteria. It is suitable for mild to moderate infections.