International journal of antimicrobial agents
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The pharmacodynamic (PD) parameters most often used in studies of antibiotic effect include the following relationships between the antibiotic concentration curve in serum as a surrogate marker for the antibiotic concentration at the infection site, the peak/minimal inhibitory concentration (MIC) ratio, the area under the curve (AUC)/MIC ratio and the duration of time the concentration exceeds the MIC (T(>MIC)). The MIC plays an important role also as a PD marker, and its precision in this respect is discussed. The predictive role of T(>MIC) is important for drugs showing minimal concentration dependent effect such as the beta-lactam antibiotics, the macrolides and others. ⋯ This is the case for aminoglycosides and fluoroquinolones, and for both classes a peak/MIC ratio of at least 10 within the first 24 h of treatment has been shown to result in around 90% bacteriological as well as clinical cure. One consequence of clinical dosing has been the once-a-day (OD) dosing for aminoglycosides, which is the standard mode of therapy in many countries. Clinical studies in the field of antibacterial PD are still relatively scarce, and much information is needed to enable relevant dosing strategies for all types of antibiotics against all common infections and micro-organisms.