Rapid metaboliser
An individual expressing a wild-type metabolic enzyme and thus displaying a level of metabolic activity in the “normal” range. An alternative term for extensive metaboliser.
Clinical Context
CYP2D6 may be responsible (at least in part) for metabolism of about one quarter of medications. Recently, there have been patient deaths highlighted in the Canadian media that have been attributed to use of codeine in ultra-rapid metabolisers. One report described the death of a pediatric patient receiving normal codeine doses post-tonsillectomy and another involved the breastfed infant of a mother who was taking codeine post-partum. Not all issues affecting rapid metabolisers are so shocking or tragic; patients that take ondansetron for the prevention of chemotherapy-induced nausea and vomiting may simply find the drug to be ineffective, and would benefit from rotation to another 5-HT3 antagonist such as granisetron that is not metabolised by CYP2D6.
