Metabolism of codeine

Wilcox, R.A. and Owen, H. (2000) Variable cytochrome P450 2D6 expression and metabolism of codeine and other opioid prodrugs implications for the Australian anaesthetist. Anaesthesia and Intensive Care, 28 (6), 611-619. 

The opioid derivatives most commonly used as antitussives are dextromethorphan, codeine, levopropoxyphene, and noscapine (levopropoxyphene and noscapine are not available in the USA). They should be used with caution in patients taking monoamine oxidase inhibitors (see Table 31-5). Antitussive preparations usually also contain expectorants to thin and liquefy respiratory secretions. Importantly, due to increasing reports of death in young children taking dextromethorphan in formulations of over-the-counter "cold/cough" medications, its use in children less than 6 years of age has been banned by the FDA. Moreover, due to variations in the metabolism of codeine, its use for any purpose in young children is being reconsidered. 

CODEINE, DIHYDROCODEINE PROTEASE INHIBITORS 1 efficacy of codeine and dihydrocodeine when given with ritonavir Inhibition of CYP2D6-mediated metabolism of codeine to its active metabolites Use an alternative opioid... 

Quinidine inhibits the hepatic metabolism of codeine to morphine. Whether this diminishes or abolishes the analgesic effect of codeine is uncertain (17,18). 

Codeine Quinidine Reduced analgesic effect Reduced liver metabolism of codeine to morphine... 

Lurcott G. The effects of the genetic absence and inhibition of CYP2D6 on the metabolism of codeine and its derivatives hydrocodone and oxycodone. Anesth Prog 1999 45 154-6. 

Yue Q-Y, Tomson T, Sawe J. Carbamazepine and cigarette smoking induce differentially the metabolism of codeine in man. Pharmacogenetics (1994) 4, 193-8. 

Rifampicin markedly increases the metabolism of codeine and morphine, and reduces their effects. Rifampicin dramatically reduced the effects of oxycodone in one patient. 

Lanreotide and octreotide partially inhibit the metabolism of codeine, which may possibly reduce its analgesic effects. 

SoDK yi A, Bochner F, Chen ZR. Lack of effect of paracetamol on the pharmacokinetics and metabolism of codeine in man. EurJ Clin Pharmacol (1991) 41,379-82. 

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