Could I have harmed a breastfed baby by taking 1 tablet of Thiocodin?

At the recommended therapeutic doses, the codeine contained in Thiocodin and its active metabolite may be present in breast milk at very low doses and are unlikely to have an adverse effect on the breastfed baby. So it seems that one tablet should not harm the baby. The maximum concentration of codeine phosphate in the blood occurs within 1 to 2 hours, and the antitussive effect lasts up to 4-8 hours, so you should take the longest possible interval between taking the drug and feeding the baby. If the patient has a very fast metabolism, there may be higher concentrations of the active metabolite morphine in breast milk and in very rare cases may cause symptoms of opioid toxicity in the baby. If any of your child's behaviour would bother you, please consult your pediatrician immediately. However, this is unlikely to happen after taking 1 tablet of Thiocodin. I am attaching a study that may be helpful: https://www.gdziepolek.pl/artykuly/leki-a-karmienie-piersia