ampicillin + aztreonam

Ampicillin + aztreonam is a combination of two beta-lactam antibiotics used together to treat infections caused by bacteria, particularly in cases where multidrug-resistant Gram-negative organisms are suspected or confirmed. Ampicillin is an aminopenicillin that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death. Aztreonam is a monobactam antibiotic that also inhibits bacterial cell wall synthesis but has a high affinity for PBP3 in Gram-negative bacteria and is resistant to many beta-lactamases produced by these organisms. The combination may be used synergistically, especially against certain resistant pathogens, as each drug covers different spectra of activity—ampicillin primarily targets Gram-positive and some Gram-negative bacteria, while aztreonam targets aerobic Gram-negative bacteria including those producing certain beta-lactamases[1][5][9]. This combination does not have a unique brand name or fixed-dose formulation approved; it is typically used off-label based on clinical judgment.

Other names

ampicillin and aztreonamampicillin plus aztreonam