Individual postoperative analgesia and gene polymorphisms of CYP3A7 and MDR1: an association study

Pain was acknowledged as a member of five vital signs. In clinical practice, anesthetic was used to alleviate pain for cancer patients undergoing surgery. Previous studies showed anesthetic sensitivity varied significantly in different races or ethnics, suggesting that anesthetic dose should be considered for individual analgesia. However, molecular mechanism of anesthetic sensitivity is still unclear. Thus, our study was focused on the association between individual postoperative analgesia and gene polymorphisms of CYP3A7 and MDR1. Consecutive gastric cancer patients were enrolled. All enrolled patients received surgery and treatment in the same hospital. Blood specimens were collected from enrolled patients. Polymorphisms of CYP3A7 and MDR1 were analyzed with PCR and PCR-RFLP. Anesthetic efficacy was evaluated for patients with different polymorphisms of CYP3A7 and MDR1, and was verified by pain scoring for fentanyl treatment. Logistic regression was performed upon age, gender, and surgery status to predict potential risk factors for high anesthetic sensitivity. Compared with gastric cancer patients with low grade of pain, patients with high grade had higher frequency of gene polymorphisms (P < 0.01), including genotype of CYP3A7 heterozygote, allele at T site of CYP3A7, genotype of MDR1 homozygous, genotype of MDR1 heterozygote and allele at G site of MDR1. Moreover, compared patients with AA genotype, patients with AG genotype had lower grade of pain, regardless of CYP3A7 or MDR1 (P < 0.01). Logistic regression demonstrated that CYP3A7 heterozygote, allele at T site of CYP3A7 and polymorphisms of MDR1 gene were risk factors upon age, gender, and surgery status for high anesthetic sensitivity. Polymorphisms of CYP3A7 and MDR1 were significantly associated with high anesthetic sensitivity in gastric cancer patients with high grade of pain. CYP3A7 heterozygote and polymorphisms of MDR1 gene could predict high anesthetic sensitivity.