Tramadol and its metabolite, O-desmethyltramadol (M1), are present in human milk. There is no information on the effects on the drug around the breastfed infant or the consequences of your drug on milk manufacturing. The M1 metabolite is more powerful than tramadol in mu opioid receptor binding [see Clinical Pharmacology https://chem874szc9.wikilinksnews.com/user