Codeine can be too risky for breastfed infants

Codeine can be harmful and even fatal to some brestfed infants, according to new evidence from Dr. Gideon Koren, director of the Motherisk Program at the Hospital for Sick Children in Toronto. Concern regarding the safety of codeine during breastfeeding arose after a two-week old infant died of an overdose of morphine acquired from breast milk. Codeine (with acetaminophen) is often given to women to control pain following childbirth. It is most commonly prescribed for mothers whose delivery invloves a surgical episiotomy or caesarean section. The drug has been considered compatible with breast feeding, according to well-recongnized guidelines published by the American Academy of Pediatrics. Codeine is an inactive prodrug of morphine. In most people only about 10% of the drug is converted to morphine. However, Koren and colleague's research found that about 5% of women are CYP2D6 ultra-rapid metabolizers. this results in significantly higher morphine concentrations in plasma and breat milk, which can lead to potentially life threatening central nervous system (CNS) depression in the breastfed infant. However, Koren notes that the adverse CNS effects are usually rapidly and completely reversible once exposure to the breast milk is discontinued.