The therapeutic monitoring of antimicrobial agents

Aims To review the basis and optimal use of therapeutic drug monitoring of antimicrobial agents. Methods Antimicrobial agents for which a reasonable case exists for therape utic drug monitoring were reviewed under the following headings: pharmacoki netics, why monitor, therapeutic range, individualisation of therapy, sampl ing times, methods of analysis, interpretative problems and cost-effectiven ess of monitoring. Results There is a strong historical case for monitoring aminoglycosides. T he recent move to once-daily dosing means that criteria for therapeutic dru g monitoring need to be redefined. Vancomycin has been monitored routinely but many questions remain about the most appropriate approach to this. A ca se can be made for monitoring teicoplanin, flucytosine and itraconazole in certain circumstances. Conclusions The approach to monitoring aminoglycosides needs to be redefine d in the light of once-daily dosing. It is premature to suggest that less s tringent monitoring is necessary as toxicity remains a problem with these d rugs. The ideal method of monitoring vancomycin remains to be defined altho ugh a reasonable case exists for measuring trough concentrations, mainly to ensure efficacy. Teicoplanin is monitored occasionally to ensure efficacy while flucytosine is monitored occasionally to avoid high concentrations as sociated with toxicity. Itraconazole has various pharmacokinetic problems a nd monitoring has been suggested to ensure that adequate concentrations are achieved.