The potential benefits of CYP2D6 genotyping were explored in a clinical trial of patients receiving opioids for chronic pain. 370 patients at 7 clinics were placed 2- to-1 to either genotyping followed by dose adjustment, or standard care. After 3 months, investigators found that pain was reduced for the poor and intermediate metabolizers receiving genotyping and dose adjustment, versus the poor and intermediate metabolizers who received standard care (P=0.016), and 24% of those two phenotypes receiving genotyping/adjustment reported an improvement of 30% or more in pain intensity (a clinically meaningful change), compared to 0% in the standard treatment group. No difference was seen in pain reduction for the normal metabolizers in the genotyping group versus normal metabolizers in the standard treatment group, emphasizing the potential for genotyping and dose adjustment for improvement of chronic pain.
“The implementation of CYP2D6-guided care was shown to be feasible and yielded clinically relevant improvements in pain control among the subset of patients most expected to benefit,” the authors concluded. “These results indicate CYP2D6 genotype testing may be a helpful addition to the primary care physician’s armamentarium in chronic pain management.”
Smith DM, Weitzel KW, Elsey AR, et al. CYP2D6-guided opioid therapy improves pain control in CYP2D6 intermediate and poor metabolizers: a pragmatic clinical trial. Genet Med. 2019 Aug;21(8):1842-1850. doi: 10.1038/s41436-018-0431-8