Variable response to opioid treatment: any genetic predictors within sight?
F Skorpen1, E A Laugsand, P Klepstad
1Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway. frank.skorpen@ntnu.no
Palliative Medicine
|June 11, 2008
Summary
Genetic variations influence opioid pain relief, but current evidence is limited. Only micro-opioid receptor gene variants show potential clinical relevance for group-level pain management, not individual prediction.
Area of Science:
- Pharmacogenetics
- Pain Management
- Genetics
Background:
- Opioid analgesia and side effects exhibit significant inter-individual variability.
- Genetic polymorphisms are hypothesized to contribute to this variability in patient response to opioids.
Purpose of the Study:
- To review and synthesize evidence linking human gene polymorphisms to variations in opioid analgesia and adverse effects.
- To identify specific genetic factors potentially influencing opioid treatment outcomes in patients with moderate to severe pain.
Main Methods:
- Literature review of studies investigating the relationship between genetic polymorphisms and opioid response.
- Analysis of evidence for specific gene variants, alleles, genotypes, and haplotypes affecting opioid efficacy and side effects.
Main Results:
- Limited evidence exists for most gene polymorphisms and opioid response.
- The micro-opioid receptor 118A>G polymorphism shows sufficient evidence for a clinically relevant effect at the group level for moderate to severe pain.
- Few genetic variants are associated with opioid adverse effects, with data often from non-palliative care populations.
Conclusions:
- Current genetic markers cannot reliably predict individual patient outcomes for opioid efficacy or adverse effects in palliative care.
- A lack of large-scale studies, standardized symptom assessment, and research specifically in palliative care settings limits definitive conclusions.
Related Concept Videos
01:29Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
01:22Opioid Receptors: Overview
Opioid receptors, including the mu (μ, MOR), delta (δ, DOR), and kappa (κ, KOR) types, belong to the rhodopsin family of G protein-coupled receptors. These receptors are located throughout the central and peripheral nervous systems and in non-neuronal tissues such as macrophages and astrocytes. Opioid receptor ligands can be categorized into agonists or antagonists. Highly selective agonists include [d-Ala2, MePhe4, Gly(ol)5]-enkephalin or DAMGO for MOR, [D-Pen2, D-Pen5]-enkephalin or DPDPE for...
01:25Analgesia and Pain Management
Pain is critical to various clinical pathologies, provoking an urgent need for effective management. Pain, whether acute or chronic, is a complex neurochemical process. Its alleviation depends on the type, with nonopioid analgesics effective for mild to moderate pain, such as musculoskeletal or inflammatory pain, while neuropathic pain responds best to anticonvulsants, tricyclic antidepressants, or serotonin/norepinephrine reuptake inhibitors. For severe acute or chronic pain, opioids may be...
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
01:20Opioid Analgesics: Morphine and Other Natural Cogeners
Opioids are a class of drugs that mimic endogenous opioid peptides and act on opioid receptors, and help in pain relief. These compounds are classified as natural, synthetic, or semi-synthetic. Natural opioids, like morphine, codeine, and thebaine, are derived from the opium poppy plant (Papaver somniferum or Papaver album) and are termed opiates. Synthetic opioids are artificial, while semi-synthetic opioids combine natural and synthetic compounds. Morphine, a prototypical opioid, possesses a...
01:15Opioid Analgesics: Synthetic and Semisynthetic Opioids
Synthetic and semisynthetic opioids are pivotal in pain management and tackling opioid addiction. Semisynthetic opioids, including morphinans (morphine derivatives), oxycodone, oxymorphone, hydrocodone, and hydromorphone, have improved pharmacokinetic profiles compared to morphine. Additionally, heroin and 6-MAM (6-Monoacetylmorphine) show better CNS penetration than morphine due to heightened lipid solubility. Hydromorphone, a potent opioid, undergoes hepatic metabolism to form the active...