When propofol is used as an anaesthetic in a breastfeeding woman, it is recommended to throw away t

Fråga: When propofol is used as an anaesthetic in a breastfeeding woman, it is recommended to throw away the milk for 1-2 days. Is there any scientific documentation for this recommendation?

Sammanfattning: The elimination half-life of propofol is short (30-60 minutes). Preliminary data suggest that transfer of propofol into milk is a minor route of elimination. However, the capacity of the infant for glucuronidation, which is the major metabolic pathway of this drug, is not known. More information is needed to predict the risk of breast feeding to the infant when the mother is receiving propofol. It seems however unlikely that the risk is big for the child if the mother receives a single dose of propofol.

Svar: Only one study was found in the Medline literature search concerning breast milk concentration of propofol (1). In this preliminary study, propofol concentrations in milk/colostrum samples were measured in 7 women undergoing cesarean section under general anesthesia. In 4 women who received 2.5 mg/kg propofol injected intravenously (based on nonpregnant body weight), propofol concentrations in the milk/colostrum were between 0.089 to 0.24 ug/ml within 4 or 8 hours after the operation. In another 3 patients who received a 2.5 mg/kg intravenous bolus plus a continuous infusion of propofol at a rate of 5.0 mg/kg/h the corresponding drug concentrations in milk were 0.04-0.74 ug/ml. These concentrations in milk are lower compared with the plasma propofol concentrations at delivery (0.056 +/- 0.08 ug/ml after intravenous bolus and 1.66 +/-0.16 after intravenous bolus plus infusion). A second milk sample was taken at 24 hours postdelivery from one patient who received an intravenous bolus plus infusion and contained about 6 per cent of the concentration in the 4 hour sample. The limited data seem to suggest that transfer of propofol into milk/colostrum was a minor route of elimination.

The main route of elimination of propofol in the adult is by glucuronidation (cf 1). The elimination half-life is 30-60 minutes (2). However the kinetics of the drug do not seem well explored and we suspect that there could be a later phase with a longer half- life. Multiple forms of glucuronyltransferase have been shown based on evidence from perinatal development studies. Certain forms of the glucuronyltransferase in the neonate are not fully developed at delivery. In such a case, theoretically, even a small proportion of a drug which has passed into milk may affect the infant. However, it is not known which isoenzyme of the glucuronyltransferase is catalyzing the glucuronidation of propofol. 1 Dailland P, Cockshott ID, Lirzin JD, Jacquinot P, Jorrot JC, Devery J, Harmey JL, Conseiller C: Intravenous propofol during cesarean section: placental transfer, concentrations in breast milk, and neonatal effects. A preliminary study. Anesthesiology 1989; 71: 827-834 2 FASS 1991; sid 326