Tramadol and its metabolite, O-desmethyltramadol (M1), are existing in human milk. There isn't a info on the results on the drug within the breastfed infant or the effects from the drug on milk generation. The M1 metabolite is more potent than tramadol in mu opioid receptor binding [see Clinical Pharmacology https://garym753rwa7.bloggerswise.com/profile