Sincalide is a synthetic octapeptide analogue of cholecystokinin. Because sincalide has a molecular weight of 1143, the amount in milk is likely to be very low and oral absorption by the infant is unlikely because it is probably destroyed in the infant's gastrointestinal tract. The serum half-life of sincalide is less than 2 minutes, indicating that withholding breastfeeding for 10 minutes after a dose should ensure that the infant is not exposed to the drug.