Effects of CYP3A5~*3 genetic polymorphism on analgesia with fentanyl

Abstract

Objective To investigate the effects of CYP3A5~* 3 genetic polymorphism on analgesia with fentanyl. Methods One hundred and eighty ASA Ⅰ or Ⅱ patients, aged 20-50 yr, Hart nationality, Henan province, scheduled for elective abdominal total hysterectomy or myomectomy under general anesthesia, were enrolled in this study. The polymorphic sites of the CYP3A5~* 3 allele were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The patients were assigned to one of 3 groups according to their genotypes: wild homozygote group, mutation heterozygote group and mutation homozygote group. Midazolam, remifentanyl, propofol and succinylcholine were used for induction of anesthesia. The patients were mechanically ventilated after tracheal intubation. Remifentanyl, propofol and atracurium were given iv for maintenance of anesthesia. The pain was assessed with visual analog scale (VAS) after consciousness was regained. When VAS score > 3, the patients were given fentanyl 20 μg every 5 min until VAS score was decreased to ≤3 and then patient-controlled intravenous analgesia (PCIA) with fentanyl was started. The background infusion rate of fentanyl 1.0 mg and droperidol 5 mg (in 100 ml normal saline) was 0.5 ml/h. The PCIA pump was programmed to give a 2 ml bolus of fentanyl solution with a 5 min lockout interval, 7 time successful delivery per hour and maximum dosage 145 μg/h, and VAS score was maintained less than 3. The amount of fentanyl used within 24 h after surgery was recorded. Results No significant difference was detected in the fentanyl consumption in the 24 h during PCIA among the 3 groups (P> 0.05). Conclusion The genetic polymorphism CYP3 A5~* 3 is not the factor contributing to the individual variation in the patient's response to analgesia with fentanyl. Key words: Cytochrome P-450 enzyme system; Polymorphism,single nucleo tide; Fentanyl; Analgesia,patient-controlled