Propofol elimination in human breast milk

Abstract

Background/Aims Lactating women having operations under general anesthesia are advised to pump and discard their milk for 24h after the procedure. We determined the kinetics of propofol elimination in breast milk to ascertain its safety after propofol administration. Methods Three lactating women were studied after giving IRB-approved written informed consent. Patients were premedicated with midazolam 5 min before induction of anesthesia with fentanyl and propofol. Anesthesia was maintained with volatile anesthetics. Milk was collected using an electric breast pump before and at 5, 7, 9, 11, and 24h after drug administration. Blood samples were collected before and at intervals up to 7h after drug administration. Plasma and milk propofol concentrations were measured by HPLC with fluorescence detection. Using SAAM II, propofol elimination in breast milk was modelled simultaneously with plasma kinetics as the cumulative amount of drug in milk just as urinary elimination is modelled, but with a delay. Results Plasma propofol kinetics were consistent with those reported by others. In 24h, only 0.04 (± 0.04)% of the propofol dose was eliminated in milk, representing less than 0.05% of the propofol elimination clearance with a delay of nearly 6h. Conclusion Consistent with the report of others for methohexital, meperidine, and diazepam, the amount of propofol eliminated in breast milk in the first 24h after induction of anesthesia provides insufficient justification for interruption of breast feeding. Clinical Pharmacology & Therapeutics (2005) 77, P39–P39; doi: 10.1016/j.clpt.2004.12.044