The pharmacokinetics of once-daily dosing with gentamicin in women with postpartum endometritis.

OBJECTIVE To evaluate the pharmacokinetics and cost of once-daily dosing with gentamicin in women with postpartum endometritis. METHODS Gentamicin in a single daily dose of 4.5 mg/kg was administered intravenously to 10 women with postpartum endometritis. Peak and trough gentamicin levels were measured, and nephrotoxicity and clinical ototoxicity were monitored. Pharmacokinetic data were analyzed, and a cost analysis of once-daily gentamicin administration was performed. RESULTS The mean elimination constant was 0.105 +/- 0.008 L/h, and the mean volume of distribution was 0.34 +/- 0.07 L/kg. Mean peak gentamicin levels exceeded 11 mg/L, and all trough levels were < 0.3 mg/L. Cost savings of 44% were achieved with once-daily dosing of gentamicin, compared with traditional thrice-daily dosing. CONCLUSIONS Once-daily dosing with gentamicin in women with postpartum endometritis achieves therapeutic peak levels without drug accumulation. Substantial cost savings are realized with this dosing regimen.