The importance of cytochrome P450 monooxygenase CYP2D6 in palliative medicine

The enzymes in the cytochrome p450 monooxygenase system (CYP) are the major enzymes responsible for metabolizing medications. The CYP2D6 isomer is res ponsible for metabolizing certain opioids, neuroleptics, antidepressants an d cardiac medications. Owing to CYP2D6's low capacity and high affinity it is easily saturated by substrate and/or inhibited, resulting in pharmacokin etic interactions. Polymorphisms of the structural gene are common, leading to wide inter-individual and ethnic differences in drug metabolism. Clinic ally important drug interactions, which may be anticipated in the palliativ e medicine population, are reviewed.