Antibiotic dose is important in determining serum area-under-the-curve (AUC) and peak serum concentration (C(max)), as well as the time the serum concentration remains over the pathogen minimum inhibitory concentration (T>MIC). However, dose is not the sole determinant of these factors; they are modified by absorption, clearance, and frequency of dosing. It is difficult to relate dose to clinical outcome in humans, but pharmacodynamic parameters (AUC/MIC, C(max)/MIC, or T>MIC) have been related to clinical and bacteriological efficacy or emergence of resistance to aminoglycosides, fluoroquinolones, glycopeptides, and beta-lactams.