Briefly Noted

The Food and Drug Administration is urging women to avoid breastfeeding if they are taking codeine or tramadol. Codeine, a pain medication, is metabolized in the liver to morphine. Tramadol is a prescription opioid medication approved for use in adults to treat pain that is severe enough to require an opioid analgesic and for which alternative treatments are inadequate. Similar to codeine, when tramadol enters the body, it is changed in the liver to its active form, O‐desmethyltramadol (known as M1). Both tramadol and M1 relieve pain and are responsible for side effects that some people may experience, but M1 has stronger opioid effects than the tramadol. The concern is some people are ultra‐rapid metabolizers of the enzyme that changes codeine to morphine and tramadol to M1. For people who are ultra‐rapid metabolizers, the specific likelihood of having an adverse event when taking codeine or tramadol is not known. In breastfeeding mothers, the ultra‐rapid conversion of codeine to morphine and tramadol to M1 can result in high and unsafe levels of morphine and M1 in blood and breast milk.