Opioid-induced Toddler deaths have transpired from breastfeeding by mothers who were being ultrarapid metabolizers taking codeine postpartum. Conversely, poor metabolizers might expertise inadequate pain relief when treated with codeine. The presence on the methyl group to the selection 3 carbon restrictions the first-pass presystemic metabolism of codeine in the liver. https://codeine.store/product/tylenol-wcodeine-3/