Effect of CYP3A4*1G gene polymorphism on pharmacokinetics and pain threshold of sufentanil after joint replacement in elderly patients

• CYP3A4*1G gene polymorphism significantly affects sufentanil pharmacokinetics in elderly joint replacement patients, with mutant genotypes showing prolonged elimination half-life and reduced clearance. • Patients with CYP3A4*1G mutations exhibit higher pain thresholds after sufentanil administration, indicating altered analgesic response. • Pain threshold is positively correlated with sufentanil plasma concentration, and this correlation is stronger in mutant genotype groups. • Genotype-guided dosing of sufentanil may improve individualized pain management in elderly patients undergoing joint replacement.