Associations of OPRM1, COMT, and ABCB1 Variants with Opioid Analgesic Response in Acute Renal Colic: A Candidate-Gene Study.

Background: Acute renal colic is a common urological emergency characterized by substantial interindividual variability in analgesic response. Pharmacogenetic variation in OPRM1, COMT, and ABCB1 may contribute to differences in opioid efficacy and pain control. This study primarily evaluated the associations of OPRM1 A118G (rs1799971), COMT Val158Met (rs4680), and ABCB1 C3435T (rs1045642) polymorphisms with opioid analgesic response in patients with acute renal colic. As a secondary exploratory analysis, genotype and allele frequencies were compared between patients and healthy controls. Methods: This prospective case-control study included 150 patients with acute renal colic and 100 healthy controls. Genotyping was performed using TaqMan SNP Genotyping Assays based on real-time polymerase chain reaction. Genotype frequencies were compared between groups using dominant and recessive genetic models, and Hardy-Weinberg equilibrium was assessed. In addition, genotype-phenotype associations were evaluated using pain severity, early analgesic response, initial opioid dose, rescue analgesic requirement, and multivariable logistic regression analyses. Results: In the secondary exploratory case-control analysis, no statistically significant differences in genotype or allele frequencies of OPRM1 rs1799971, COMT rs4680, or ABCB1 rs1045642 were observed between patients with acute renal colic and healthy controls. Within the patient cohort, however, genotype-phenotype analyses identified differences in early analgesic outcomes. Baseline-adjusted 30 min VAS differed according to OPRM1, COMT, and ABCB1 genotype, with the most pronounced difference observed for ABCB1 rs1045642. Patients with the ABCB1 TT genotype had higher adjusted 30 min VAS scores and showed a pattern of greater opioid requirement and more frequent rescue analgesia. In exploratory multivariable analysis, the ABCB1 TT genotype was associated with higher odds of inadequate early analgesic response (adjusted OR = 2.74, 95% CI 1.18-6.37; p = 0.019). Given the limited number of outcome events, this adjusted association should be considered preliminary and hypothesis-generating. Conclusions: No significant differences in the distributions of the polymorphisms investigated were observed between patients with acute renal colic and healthy controls. Within the patient group, ABCB1 genetic variation was associated with early opioid analgesic response, although this finding should be considered preliminary and requires confirmation in larger prospective pharmacogenetic studies before clinical implementation. Any potential future pharmacogenetic application should be considered as an adjunct to established first-line renal-colic management and specifically in patients for whom opioid therapy is clinically indicated.