Review of gentamicin therapy based on pharmacokinetics

The feasibility of using pharmacokinetic estimations of drug serum levels to evaluate gentamicin use was explored. A consecutive series of 40 adult patients who received nonprophylactic "piggyback" gentamicin therapy was retrospectively evaluated. Traditional factors in the evaluation of antibiotic use, such as identity of microbe and sensitivity to antibiotic, were monitored. Additionally, peak and trough drug serum levels were computed for each patient. These were compared with toxic serum levels and minimum inhibitory concentrations as reported in the literature. Certain factors, such as duration of therapy and existence of alternate antibiotic therapy, suggested less than optimal therapy in the study patients. However, computed serum levels revealed that the patients experienced both safe and effective peak and trough gentamicin levels. Only with the use of pharmacokinetic estimations of drug serum levels could a comprehensive conclusion be reached regarding the appropriateness of therapy. Gentamicin therapy was generally rational in the study group. The use of pharmacokinetic principles in the calculation of serum levels may be a useful tool in drug use studies.