[Therapeutic antimicrobial agents for postoperative infections: appropriate use of antibiotics from the viewpoint of pharmacokinetic/pharmacodynamic theory].

Pharmacokinetic/pharmacodynamic (PK/PD) parameters can be used predict the potential for bacterial eradication with antimicrobial therapy. The validity of these parameters is supported by both animal and clinical studies. Two major patterns of antimicrobial activities are time-dependent killing and concentration-dependent killing. Time-dependent killing is characteristic of beta-lactams. The major PK/PD parameter correlating with efficacy is a serum concentration of 50-60% for cephalosporins and 3040% for carbapenems in the dosing interval, and these concentrations are the susceptibility limits for the dosing regimens used. It is recommended that these types of antibiotic be administered 3-4 times per day. Concentration-dependent killing is characteristic of aminoglycosides. The major PK/PD parameter correlating with the efficacy of these agents is the 24-h area under the curve or peak serum level. This type of antibiotic should be administered as the total daily dose once daily.