Exploratory study on association of single-nucleotide polymorphisms with hydromorphone analgesia in ED

Influence of COMT (rs4680) and OPRM1 (rs1799971) on Cancer Pain, Opioid Dose, and Adverse Effects

Background: The influence of pharmacogenomics on opioid response, particularly with COMT (rs4680) and OPRM1 (rs1799971) variants, has been studied individually and in combination. However, most studies are in a noncancer context and not all their possible variant combinations have been examined. Objectives: This study examined COMT (rs4680) and OPRM1 (rs1799971), and their allele combinations, in advanced cancer to examine associations with pain scores, opioid dose, and adverse effects. Setting/Subjects: This multicenter prospective cohort study recruited patients receiving opioids for advanced cancer pain in Melbourne, Australia. Clinical data (demographics, opioids), validated instruments (pain and adverse effects), and blood (DNA) were collected. Descriptive analyses were used. Univariate and multivariate logistic regression analyses were used to evaluate associations between clinical outcomes (opioid dose, pain, adverse effects) and genotypes of interest. Results: Fifty-four participants were recruited to the study. Those with COMT A allele required lower opioid doses [130 mg (interquartile range [IQR] 67.5,230) versus 180 mg (IQR 55,322.5), p = 0.047] and experienced greater adverse effects [sickness response aOR (adjusted odds ratio) 7.1 (95% CI 1.51,33.41), p = 0.01]. Those with the COMT GG/OPRM1 G allele combination required higher opioid doses [322.5 mg (IQR 264,360) versus 125 mg (65,225), (p = 0.04)]. Those with COMT AG/OPRM1 AA experienced higher average pain [aOR 1.55 (95% CI 1.03, 2.33), p = 0.04] and moderate-severe nausea [aOR 5.47 (95% CI 1.35, 22.21), p = 0.02] but reduced drowsiness [aOR 0.25 (95% CI 0.06, 1.02), p = 0.05]. Conclusions: Patients with cancer with the COMT alternate (A) allele have greater sickness response adverse effects, which may be responsible for the lower opioid doses observed. Significant results of two new COMT/OPRM1 genotype combinations are presented that have not previously been studied, with plausible phenotype descriptions suggested.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.