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Polymorphic cytochrome P450 2D6 as the responsible enzyme of activation 

Polymorphic cytochrome P450 2D6 as the responsible enzyme of activation
Polymorphic cytochrome P450 2D6 as the responsible enzyme of activation

Ingolf Cascorbi

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date: 24 September 2021

The landmark paper discussed in this chapter is ‘Bioactivation of the narcotic drug codeine in human liver is mediated by the polymorphic monooxygenase catalyzing debrisoquine 4-hydroxylation (cytochrome P-450 dbl/bufI)’, published by Dayer et al. in 1988. Codeine is an old but frequently prescribed drug used for the treatment of mild-to-moderate pain. However, its use is nowadays restricted after observations of partly fatal respiratory repression in children. Codeine itself exhibits no analgesic effect, but is partly activated by O-demethylation to morphine by cytochrome P450 2D6 (CYP2D6). The identification of the polymorphic CYP2D6 as the enzyme responsible for activation was achieved by Dayer et al. in 1998 and was an important milestone contributing to the widely observed inter-individual differences of drug action and side effects of codeine. Translating the pharmacogenetics of codeine into clinical practice is currently underway in clinical trials, to identify ineffective analgesics and, in particular, avoid severe adverse events.

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