Lack of Association of OPRM1 and ABCB1 Single‐Nucleotide Polymorphisms to Oxycodone Response in Postoperative Pain

PURPOSE: The aim of the study was to search for an association between the single-nucleotide polymorphisms A118G in OPRM1 and C3435T and G2677T/A in ABCB1 and the analgesic effect of intravenous oxycodone in postoperative pain. METHODS: There were 268 patients with postoperative pain after, primarily, thyroidectomy. At given times during the first 24 hours postoperatively, their pain was rated at rest and during activity according to a numeric rating scale (0 = no pain, 10 = worst possible pain) and calculated as pain time area under the curve0-24 hours . A negative answer in a final questionnaire and/or the use of rescue medication categorized a patient as a nonresponder. RESULTS: For OPRM1, there was no difference found between the wild type and the variant allele in the percentages of nonresponders (118AA = 16.4% vs 118AG/118GG = 17.0%, P = 1.0) or in the pain ratings. For ABCB1, no difference was found between the wild type and the variant alleles for single-nucleotide polymorphism tested as percentages of nonresponders (3435CC = 17.5% vs 3435CT/3435TT = 15.8%, P = .85; 2677GG = 17.8% vs 2677GT/2677TT = 15.8%, P = .74) or pain ratings. CONCLUSION: No association was found between the tested single-nucleotide polymorphisms in OPRM1 and ABCB1 and changes in the analgesic effect of oxycodone.