Analgesic requirements after major abdominal surgery are associated with OPRM1 gene polymorphism genotype and haplotype.
ABSTRACT The association between SNPs of the human OPRM1 gene encoding the micro-opioid receptor and postoperative analgesic requirements in surgical patients remains controversial. Here, we evaluate whether any of the five tag SNPs (A118G, IVS2+G691C, IVS3+G5953A, IVS3+A8449G and TAA+A2109G) representing the four linkage disequilibrium blocks of the OPRM1 gene influences postoperative analgesic requirements.
We studied 138 adult Japanese patients who underwent major open abdominal surgery under combined general and epidural anesthesia and received continuous postoperative epidural analgesia with opioids.
The 118G homozygous (GG) patients required 24-h postoperative analgesics more than 118A homozygous (AA) and heterozygous (AG) patients. Tag SNP haplotypes also were associated with 24-h postoperative analgesic requirements.
These results suggest that OPRM1 gene tag SNP genotypes and haplotypes can primarily contribute to prediction of postoperative analgesic requirements in individual patients undergoing major open abdominal surgery.
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ABSTRACT: The μ1 opioid receptor (OPRM1) genetic variant A118G results in decreased μ-receptor binding potential in the brain and increases morphine requirement. We hypothesized that OPRM1 A118G polymorphism will affect morphine-induced respiratory depression (MIRD) risk in children receiving morphine. A prospective genotype-blinded study was conducted in 88 healthy adolescents (11-18 years; 67% female, 85% Caucasian) who underwent spine fusion for scoliosis. They were followed for 48 h postoperatively for MIRD, pain scores, morphine consumption and use of analgesic adjuvants. Patients were genotyped for OPRM1 A118G variant-76% were wild type (AA) and 24% heterozygous/homozygous for variant (AG/GG). Multivariable logistic regression showed that the risk of MIRD in patients with AA genotype was significantly higher (odds ratio 5.6, 95% CI: 1.4-37.2, P=0.030). Presence of G allele was associated with higher pain scores (effect size 0.73, P=0.045). This novel association is an important step toward predicting MIRD susceptibility and personalizing morphine use.The Pharmacogenomics Journal advance online publication, 30 September 2014; doi:10.1038/tpj.2014.59.The Pharmacogenomics Journal 09/2014; 15(3). DOI:10.1038/tpj.2014.59 · 5.51 Impact Factor
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ABSTRACT: Genetic variants, such as single-nucleotide polymorphisms (SNPs), of the μ-opioid receptor gene (OPRM1) might be associated with individual differences in opioid sensitivity, as well as with the incidence and severity of postoperative nausea and vomiting (PONV). The goal of the present study was to determine, in a cohort of Japanese surgical patients, genotypes and haplotypes of several SNPs in the OPRM1 gene, and their association with PONV during the early (first 24 h) postoperative period. We examined the incidence and severity of PONV, during the first 24 h after surgery, in 85 Japanese patients receiving intravenous patient-controlled analgesia fentanyl analgesia for postoperative pain control. Eight tag SNPs of the OPRM1 gene (rs1799971, A/G; rs510769, G/A; rs4870266, G/A; rs3798683, G/A; rs1323042, A/C; rs609623, C/T; rs9397685, A/G; and rs644261, C/G) were selected based on their minor allele frequency (>10 %) and linkage disequilibrium strength (<80 %), and genotyped for haplotype analysis and determination of associations with PONV. Only one out of eight investigated SNPs, rs9397685, in the intronic part of the OPRM1 gene was associated with differences in the occurrence and severity of PONV. We also found four common haplotypes with a frequency of >10 % in the investigated patients, including GGGAACAC (33 %), AGGGACAC (19 %), GGGAACGC (12 %), and AGAGACAC (10 %). The severity of PONV in carriers of the GGGAACGC haplotype was significantly lower than in the carriers of the other haplotypes (P < 0.05). One intronic SNP, rs9397685, and haplotypes constructed from eight SNPs within the OPRM1 gene locus might be involved in the severity of PONV associated with general anesthesia and opioid administration. This novel finding, if validated and verified in larger and additional ethnic cohorts, might contribute to better knowledge of the contribution of the OPRM1 gene to PONV.Experimental Brain Research 05/2014; DOI:10.1007/s00221-014-3987-9 · 2.17 Impact Factor
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ABSTRACT: The analgesic efficacy of opioids is well known to vary widely among individuals, and various factors related to individual differences in opioid sensitivity have been identified. However, a prediction model to calculate appropriate opioid analgesic requirements has not yet been established. The present study sought to construct prediction formulas for individual opioid analgesic requirements based on genetic polymorphisms and clinical data from patients who underwent cosmetic orthognathic surgery and validate the utility of the prediction formulas in patients who underwent major open abdominal surgery. To construct the prediction formulas, we performed multiple linear regression analyses using data from subjects who underwent cosmetic orthognathic surgery. The dependent variable was 24-h postoperative or perioperative fentanyl use, and the independent variables were age, gender, height, weight, pain perception latencies (PPL), and genotype data of five single-nucleotide polymorphisms (SNPs). To examine the utility of the prediction formulas, we performed simple linear regression analyses using subjects who underwent major open abdominal surgery. Actual 24-h postoperative or perioperative analgesic use and the predicted values that were calculated using the multiple regression equations were incorporated as dependent and independent variables, respectively. Multiple linear regression analyses showed that the four SNPs, PPL, and weight were retained as independent predictors of 24-h postoperative fentanyl use (R2 = 0.145, P = 5.66 × 10-10) and the two SNPs and weight were retained as independent predictors of perioperative fentanyl use (R2 = 0.185, P = 1.99 × 10-15). Simple linear regression analyses showed that the predicted values were retained as an independent predictor of actual 24-h postoperative analgesic use (R2 = 0.033, P = 0.030) and perioperative analgesic use (R2 = 0.100, P = 1.09 × 10-4), respectively. We constructed prediction formulas, and the possible utility of these prediction formulas was found in another type of surgery.PLoS ONE 01/2015; 10(1):e0116885. DOI:10.1371/journal.pone.0116885 · 3.53 Impact Factor