Pivmecillinam (referred to as Amdinocillin Pivoxil in North America) is the pivoxil ester form of mecillinam (Amdinocillin), a semisynthetic, broad spectrum beta-lactam penicillin with antibacterial activity against gram-negative organisms. It is broken down to mecillinam (amdinocillin) in the intestinal mucosa. Amdinocillin specifically binds to and inactivates penicillin-binding protein 2 (PBP 2) located on the inner membrane of the bacterial cell wall. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This interrupts bacterial cell wall synthesis and results in the weakening of the bacterial cell wall, eventually causing cell lysis.