Genetic Variants Influencing Patient Response to Opioid Therapy

Almost every nurse can relate to examples in which an individual receiving a high dose of an opioid had no analgesic effect, whereas another experienced respiratory compromise with a small dose. In many cases, variant responses can be attributed to genetic influences responsible for metabolism of the opioid through the cytochrome p450 system (CYP), including CYP2D6, CYP3A, and CYP2B6. Variants of the mu receptor can also affect the affinity of the opioid for its receptor. A discussion of some common alleles (polymorphisms) associated with variable response to opioids is included in this article.