Serum gentamicin concentrations in postpartum endomyometritis

Gentamicin in combination with other antibiotics is frequently used in the treatment of postpartum endomyometritis. The need to monitor and maintain therapeutic concentrations, however, is controversial. To assess the role of monitoring, serum gentamicin concentrations were prospectively studied in an obstetric population treated for postpartum endomyometritis. Clinical course was correlated to serum gentamicin levels obtained using a 1 mg/kg/dose regimen. No patient demonstrated therapeutic concentrations. Sixteen of 18 obstetric patients (88%) exhibited a clinical response despite subtherapeutic serum gentamicin concentrations. The two failures included one case of septicemia and one wound seroma. Serum gentamicin levels of this obstetric population when compared to those from a gynecologic population treated for benign disease demonstrated no statistical difference. These data suggest that clinical response provides an accurate indication of the efficacy of therapy and that gentamicin doses of 1 mg/kg/dose provide sufficient antibiotic coverage in most cases. These results do not support the use of increased gentamicin dosages and the need to attain therapeutic levels in the obstetric patient, as previously suggested.