An Observational Study on the Pharmacokinetics of Levofloxacin in Lactating Atypical Pneumonia Patients

Atypical pneumonia during the postpartum period may alter drug pharmacokinetics through inflammation-related changes in vascular permeability, yet the disposition of levofloxacin into breastmilk in this population had not been characterized. This observational study measured levofloxacin concentrations in breastmilk from 10 lactating patients with atypical pneumonia receiving 400 mg once daily, using a validated HPLC method, with pharmacokinetic parameters calculated by non-compartmental analysis in Phoenix WinNonlin and compared against historical healthy-control data. Peak milk concentrations and elimination half-lives were broadly consistent with expectations, and the estimated infant daily exposure through breastfeeding was calculated at under 10% of the therapeutic infant dose across both sampling cohorts. The authors conclude that breastfeeding can likely continue cautiously during maternal levofloxacin therapy, while recommending avoidance of nursing at peak drug concentration and continued monitoring of the infant.