Pharmacodynamics of antimicrobial agents. Bactericidal and postantibiotic effects.

The effectiveness of antibiotic dosing regimens may be strongly influenced by the effects that drug concentrations at the site of infection have on bacterial population dynamics during the interval after a single dose and the cumulative effects after multiple, intermittent doses. These pharmacodynamic effects involve: (1) the rate and extent of bactericidal action and suppression of bacterial growth in tissues, and (2) persistent postantibiotic antibacterial effects. Antimicrobial agents may each exhibit unique pharmacodynamic effects that can vary with the site of infection and species of microorganism.