Pharmacogenomics and Personalized Medicine (Oct 2018)
CYP2D6 genotype can help to predict effectiveness and safety during opioid treatment for chronic low back pain: results from a retrospective study in an Italian cohort
Abstract
Concetta Dagostino,1,2 Massimo Allegri,2–4 Valerio Napolioni,5 Simona D’Agnelli,1 Elena Bignami,1 Antonio Mutti,1 Ron HN van Schaik6 1Department of Medicine and Surgery, University of Parma, Parma 43126, Italy; 2Study In Multidisciplinary Pain Research (SIMPAR), Milan 20100, Italy; 3Anesthesia and Intensive Care Department, IRCCS Multi Medica Hospital, Milan 20099, Italy; 4Italian Pain Institute, Milan 20100, Italy; 5Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA; 6Department of Clinical Chemistry, Erasmus MC, 3000 Rotterdam, The Netherlands Background: Opioids are widely used for chronic low back pain (CLBP); however, it is still unclear how to predict their effectiveness and safety. Codeine, tramadol and oxycodone are metabolized by CYP/CYP450 2D6 (CYP2D6), a highly polymorphic enzyme linked to allele-specific related differences in metabolic activity.Purpose: CYP2D6 genetic polymorphisms could potentially help to predict the effectiveness and safety of opioid-based drugs in clinical practice, especially in the treatment of CLBP.Patients and methods: A cohort of 224 Italian patients with CLBP treated with codeine or oxycodone was retrospectively evaluated to determine whether adverse reactions and effectiveness were related to CYP2D6 single-nucleotide polymorphisms. CYP2D6 genotyping was performed using the xTAG® CYP2D6 Kit v3 (Luminex) to determine CYP2D6 metabolizer phenotype (poor, intermediate, rapid and ultrarapid). Subjects from the cohort were categorized into two groups according to the occurrence of side effects (Case) or benefit (Control) after chronic analgesic treatment. The impact of CYP2D6 polymorphism on treatment outcome was tested at the metabolizer phenotype, diplotype and haplotype levels.Results: CYP2D6 polymorphism was significantly associated with opioid treatment outcome (Omnibus P=0.018, for both global haplotype and diplotype distribution test). CYP2D6*6 and *9 carriers, alleles characterized by a reduced (*9) or absent (*6) enzymatic activity, were significantly (P<0.05) associated with therapeutic failure. CYP2D6 ultrarapid metabolizers (CYP2D6*2N patients) showed an increased risk of side effects, as would be predicted. Despite their low frequency, CYP2D6 *1/*11, *4/*6 and *41/* 2N diplotypes showed significant (P<0.05) associations of efficacy and side effects with chronic opioid treatment.Conclusion: Our results showed that reduced CYP2D6 activity is correlated with lack of therapeutic effect. We found that the pharmacogenetic analysis of CYP2D6 could be helpful in foreseeing the safety and effectiveness of codeine or oxycodone treatment in CLBP. Keywords: polymorphisms, pharmacogenetics, codeine, oxycodone, analgesic drugs, personalized medicine
