A non-synonymous single nucleotide polymorphism in an OPRM1 splice variant is associated with fentanyl-induced emesis in women undergoing minor gynaecological surgery.
In carriers of the mutated G118 allele of the mu-opioid receptor, the potency of the pupil-constricting effects of morphine-6-glucuronide and morphine was significantly smaller, and carriers of the G118 allele reported less nausea and vomited less often after administration of morphine-6-glucuronide.