N&PD Moderators: Skorpio Forums Media, Science and Research Neuroscience and Pharmacology Discussion The CYP2D6 mediated o-demethylation of codeine and the 'ceiling effect' JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding. You are using an out of date browser. It may not display this or other websites correctly.You should upgrade or use an alternative browser. Members who reacted to message #18 All (1) Like (1) Nov 2, 2024 TheJuner Bluelighter Messages 79 Reaction score 37 Points 30 Loading… Forums Media, Science and Research Neuroscience and Pharmacology Discussion The CYP2D6 mediated o-demethylation of codeine and the 'ceiling effect'