Opioid analgesic which is used for treatment of chronic pain. At latest update, relevant data on its excretion into breast milk were not found. Despite of a low molecular weight and a low serum-protein binding capacity that would favor excretion into the milk, its high value of volume distribution would permit a shorter permanence in the blood that would hamper its excretion. A low oral bioavailability would hamper absorption from ingested mother's milk, except among newborn infants o prematures, who may attain an increased absorption capacity. The risk for the infants would be minimized if the breast feed is avoided within 1 to 4 hours (non-depot formulation), or, within 3 to 6 hours (depot formulation) after taking medication. Until more information on this drug is available, other options that are known to be safer are recommended, especially when the baby is a newborn or a premature. Follow-up of symptoms as sedation or gastrointestinal disorders is recommended.