Pharmacokinetic/Pharmacodynamic Considerations in Community-Acquired Lower Respiratory Tract Infections

Abstract

To accomplish the goal of both clinical and microbiological cure in the treatment of lower respiratory tract infections, microbiological data along with pharmacokinetic and pharmacodynamic data should be used. Recent studies have determined 2important antibacterial pharmacokinetic/ pharmacodynamic parameters that differ among classes of antimicrobial agents. The 2major groups include the antibiotics that exhibit concentration-dependent killing with a postantibiotic effect and time-dependent killing with minimal to moderate postantibiotic effects. For drugs that are concentration dependent (aminoglycosides, fluoroquinolones), the area under the concentration-time curve (AUC/MIC) is the most important predictor of bacteriological eradication. Alternatively, for antibiotics that exhibit time-dependent killing (-lactams, macrolides), time above the MIC ( T >MIC) is probably the major parameter that determines efficacy. Using these parameters provides the tools needed for appropriate antibiotic dosing.