Genetic Variation A118G in the OPRM1 Gene Underlies the Dimorphic Response to Epidural Opioid-Induced Itch
Xiaomeng Zhou1 · Ai‑Lun Li1 · Wan‑Jie Du1 · Pengyu Gao1 · Bin Lai1 · Fang Fang1 · Qingjian Han1 · Jing Cang11 Department of Anesthesia, Department of Pain Medicine, Zhongshan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
Abstract
Neuraxial opioids, widely used in obstetric and perioperative pain management, often lead to unwanted itch, reducing patient satisfaction. While the μ-opioid receptor has been implicated in opioid-induced itch, the genetic basis for variable itch incidence remains unknown. This study examined 3616 patients receiving epidural opioids, revealing an itch occurrence of 26.55%, with variations among opioid types and gender. Analysis of the OPRM1 gene identified six single-nucleotide polymorphisms, notably rs1799971 (A118G), that correlated with opioid-induced itch. Mouse models with an equivalent A112G mutation showed reduced neuraxial opioid-induced itch and light touch-evoked itch, mirroring human findings. The 118G allele demonstrated an anti-itch effect without impacting analgesia, addiction, or tolerance, offering insights for risk stratification and potential anti-itch pretreatment strategies.
Keywords
Itch; Opioids; MOR; SNPs
