action of the combination is significantly greater than the sum of the actions of each component.

 

• sequential inhibition of successive steps in metabolism (trimethoprim-sulfonamide)
• sequential inhibition of cell wall synthesis (mecillinam-ampicillin)
• facilitation of drug entry of one antibiotic by another (beta-lactam – aminoglycoside)
• inhibition of inactivating enzymes (ampicillin – clavulanic acid)
• prevention of emergence of resistant populations (erythromycin – rifampin)