The pharmacokinetics of a single intravenous dose of metronidazole in pregnant patients.

The pharmacokinetics of a single 500 mg intravenous dose of metronidazole administered prophylactically to 16 women undergoing caesarean sections was studied. Seven cases satisfied the criteria for a one-compartment pharmacokinetic model, eight for a two-compartment model and one for a three compartment model. The mean elimination half-life of 6.9 (+/- 2.7)h and the plasma clearance rate of 1.19 (+/- 0.33)ml/min/kg was in close agreement with previous work on non-pregnant patients. Rapid transfer across the placental barrier was found, with effective concentrations in the arterial cord plasma.