1
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Grgic J. What is the Effect of Paracetamol (Acetaminophen) Ingestion on Exercise Performance? Current Findings and Future Research Directions. Sports Med 2022; 52:431-439. [PMID: 35038139 DOI: 10.1007/s40279-021-01633-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2021] [Indexed: 12/19/2022]
Abstract
In recent years, studies have explored the effects of paracetamol (acetaminophen) ingestion on exercise performance. However, due to the contrasting findings, there is still no consensus on this topic. This article provides an overview of the effects of paracetamol on endurance, sprinting, and resistance exercise performance. Studies have reported that paracetamol ingestion may be ergogenic for endurance performance. These effects occur when paracetamol is ingested 45-60 min before exercise and appear to be more pronounced in time-to-exhaustion versus time-trial tests. Besides endurance, paracetamol ingestion 30 min before exercise increases mean power during repeated cycling sprints in interval training involving repeated 30-s all-out bouts. Preliminary data on paracetamol ingestion also suggest: (a) improved endurance performance in the heat; (b) an improvement in single sprint performance, at least when paracetamol is ingested following exercise-induced fatigue; and (c) attenuation of the decline in muscular strength that occurs with repeated maximum contractions. An ergogenic effect of paracetamol is most commonly observed when a dose of 1500 mg is ingested 30-60 min before exercise. Despite these performance-enhancing effects, the aim of this article is not to promote paracetamol use, as side effects associated with its consumption and ethical aspects need to be considered before utilizing paracetamol as an ergogenic aid. Future research on this topic is still needed, particularly related to paracetamol dosing, timing of ingestion, and the effects of paracetamol in females and elite athletes.
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Affiliation(s)
- Jozo Grgic
- Institute for Health and Sport, Victoria University, Melbourne, Australia.
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2
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Hoshijima H, Hunt M, Nagasaka H, Yaksh T. Systematic Review of Systemic and Neuraxial Effects of Acetaminophen in Preclinical Models of Nociceptive Processing. J Pain Res 2021; 14:3521-3552. [PMID: 34795520 PMCID: PMC8594782 DOI: 10.2147/jpr.s308028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 09/11/2021] [Indexed: 12/29/2022] Open
Abstract
Acetaminophen (APAP) in humans has robust effects with a high therapeutic index in altering postoperative and inflammatory pain states in clinical and experimental pain paradigms with no known abuse potential. This review considers the literature reflecting the preclinical actions of acetaminophen in a variety of pain models. Significant observations arising from this review are as follows: 1) acetaminophen has little effect upon acute nociceptive thresholds; 2) acetaminophen robustly reduces facilitated states as generated by mechanical and thermal hyperalgesic end points in mouse and rat models of carrageenan and complete Freund’s adjuvant evoked inflammation; 3) an antihyperalgesic effect is observed in models of facilitated processing with minimal inflammation (eg, phase II intraplantar formalin); and 4) potent anti-hyperpathic effects on the thermal hyperalgesia, mechanical and cold allodynia, allodynic thresholds in rat and mouse models of polyneuropathy and mononeuropathies and bone cancer pain. These results reflect a surprisingly robust drug effect upon a variety of facilitated states that clearly translate into a wide range of efficacy in preclinical models and to important end points in human therapy. The specific systems upon which acetaminophen may act based on targeted delivery suggest both a spinal and a supraspinal action. Review of current targets for this molecule excludes a role of cyclooxygenase inhibitor but includes effects that may be mediated through metabolites acting on the TRPV1 channel, or by effect upon cannabinoid and serotonin signaling. These findings suggest that the mode of action of acetaminophen, a drug with a long therapeutic history of utilization, has surprisingly robust effects on a variety of pain states in clinical patients and in preclinical models with a good therapeutic index, but in spite of its extensive use, its mechanisms of action are yet poorly understood.
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Affiliation(s)
- Hiroshi Hoshijima
- Department of Anesthesiology, Saitama Medical University Hospital, Saitama, Japan
| | - Matthew Hunt
- Departments of Anesthesiology and Pharmacology, University of California, San Diego Anesthesia Research Laboratory, La Jolla, CA, USA
| | - Hiroshi Nagasaka
- Department of Anesthesiology, Saitama Medical University Hospital, Saitama, Japan
| | - Tony Yaksh
- Departments of Anesthesiology and Pharmacology, University of California, San Diego Anesthesia Research Laboratory, La Jolla, CA, USA
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3
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De Ridder D, Adhia D, Vanneste S. The anatomy of pain and suffering in the brain and its clinical implications. Neurosci Biobehav Rev 2021; 130:125-146. [PMID: 34411559 DOI: 10.1016/j.neubiorev.2021.08.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/09/2021] [Accepted: 08/13/2021] [Indexed: 02/08/2023]
Abstract
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Chronic pain, with a prevalence of 20-30 % is the major cause of human suffering worldwide, because effective, specific and safe therapies have yet to be developed. It is unevenly distributed among sexes, with women experiencing more pain and suffering. Chronic pain can be anatomically and phenomenologically dissected into three separable but interacting pathways, a lateral 'painfulness' pathway, a medial 'suffering' pathway and a descending pain inhibitory pathway. One may have pain(fullness) without suffering and suffering without pain(fullness). Pain sensation leads to suffering via a cognitive, emotional and autonomic processing, and is expressed as anger, fear, frustration, anxiety and depression. The medial pathway overlaps with the salience and stress networks, explaining that behavioural relevance or meaning determines the suffering associated with painfulness. Genetic and epigenetic influences trigger chronic neuroinflammatory changes which are involved in transitioning from acute to chronic pain. Based on the concept of the Bayesian brain, pain (and suffering) can be regarded as the consequence of an imbalance between the two ascending and the descending pain inhibitory pathways under control of the reward system. The therapeutic clinical implications of this simple pain model are obvious. After categorizing the working mechanisms of each of the available treatments (pain killers, psychopharmacology, psychotherapy, neuromodulation, psychosurgery, spinal cord stimulation) to 1 or more of the 3 pathways, a rational combination can be proposed of activating the descending pain inhibitory pathway in combination with inhibition of the medial and lateral pathway, so as to rebalance the pain (and suffering) pathways.
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Affiliation(s)
- Dirk De Ridder
- Section of Neurosurgery, Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
| | - Divya Adhia
- Section of Neurosurgery, Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Sven Vanneste
- Global Brain Health Institute, Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
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4
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Freo U, Ruocco C, Valerio A, Scagnol I, Nisoli E. Paracetamol: A Review of Guideline Recommendations. J Clin Med 2021; 10:jcm10153420. [PMID: 34362203 PMCID: PMC8347233 DOI: 10.3390/jcm10153420] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 07/11/2021] [Accepted: 07/28/2021] [Indexed: 02/06/2023] Open
Abstract
Musculoskeletal pain conditions are age-related, leading contributors to chronic pain and pain-related disability, which are expected to rise with the rapid global population aging. Current medical treatments provide only partial relief. Furthermore, non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are effective in young and otherwise healthy individuals but are often contraindicated in elderly and frail patients. As a result of its favorable safety and tolerability record, paracetamol has long been the most common drug for treating pain. Strikingly, recent reports questioned its therapeutic value and safety. This review aims to present guideline recommendations. Paracetamol has been assessed in different conditions and demonstrated therapeutic efficacy on both acute and chronic pain. It is active as a single agent and is additive or synergistic with NSAIDs and opioids, improving their efficacy and safety. However, a lack of significant efficacy and hepatic toxicity have also been reported. Fast dissolving formulations of paracetamol provide superior and more extended pain relief that is similar to intravenous paracetamol. A dose reduction is recommended in patients with liver disease or malnourished. Genotyping may improve efficacy and safety. Within the current trend toward the minimization of opioid analgesia, it is consistently included in multimodal, non-opioid, or opioid-sparing therapies. Paracetamol is being recommended by guidelines as a first or second-line drug for acute pain and chronic pain, especially for patients with limited therapeutic options and for the elderly.
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Affiliation(s)
- Ulderico Freo
- Anesthesiology and Intensive Care, Department of Medicine—DIMED, University of Padua, 35122 Padua, Italy;
- Correspondence: ; Tel.: +39-049-821-3090
| | - Chiara Ruocco
- Center for the Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, 20129 Milan, Italy; (C.R.); (E.N.)
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia, 25100 Brescia, Italy;
| | - Irene Scagnol
- Anesthesiology and Intensive Care, Department of Medicine—DIMED, University of Padua, 35122 Padua, Italy;
| | - Enzo Nisoli
- Center for the Study and Research on Obesity, Department of Biomedical Technology and Translational Medicine, University of Milan, 20129 Milan, Italy; (C.R.); (E.N.)
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5
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Cobo MM, Hartley C, Gursul D, Andritsou F, van der Vaart M, Schmidt Mellado G, Baxter L, Duff EP, Buckle M, Evans Fry R, Green G, Hoskin A, Rogers R, Adams E, Moultrie F, Slater R. Quantifying noxious-evoked baseline sensitivity in neonates to optimise analgesic trials. eLife 2021; 10:e65266. [PMID: 33847561 PMCID: PMC8087440 DOI: 10.7554/elife.65266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 03/17/2021] [Indexed: 01/18/2023] Open
Abstract
Despite the high burden of pain experienced by hospitalised neonates, there are few analgesics with proven efficacy. Testing analgesics in neonates is experimentally and ethically challenging and minimising the number of neonates required to demonstrate efficacy is essential. EEG (electroencephalography)-derived measures of noxious-evoked brain activity can be used to assess analgesic efficacy; however, as variability exists in neonate's responses to painful procedures, large sample sizes are often required. Here, we present an experimental paradigm to account for individual differences in noxious-evoked baseline sensitivity which can be used to improve the design of analgesic trials in neonates. The paradigm is developed and tested across four observational studies using clinical, experimental, and simulated data (92 neonates). We provide evidence of the efficacy of gentle brushing and paracetamol, substantiating the need for randomised controlled trials of these interventions. This work provides an important step towards safe, cost-effective clinical trials of analgesics in neonates.
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Affiliation(s)
- Maria M Cobo
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biologicas y AmbientalesQuitoEcuador
| | - Caroline Hartley
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | - Deniz Gursul
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | | | | | | | - Luke Baxter
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | - Eugene P Duff
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
- Wellcome Centre for Integrative Neuroimaging, University of OxfordOxfordUnited Kingdom
| | - Miranda Buckle
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | - Ria Evans Fry
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
- Newborn Care Unit, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation TrustOxfordUnited Kingdom
| | - Gabrielle Green
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | - Amy Hoskin
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | - Richard Rogers
- Department of Anaesthetics, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation TrustOxfordUnited Kingdom
| | - Eleri Adams
- Newborn Care Unit, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation TrustOxfordUnited Kingdom
| | - Fiona Moultrie
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
| | - Rebeccah Slater
- Department of Paediatrics, University of OxfordOxfordUnited Kingdom
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6
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Ayoub SS. Paracetamol (acetaminophen): A familiar drug with an unexplained mechanism of action. Temperature (Austin) 2021; 8:351-371. [PMID: 34901318 PMCID: PMC8654482 DOI: 10.1080/23328940.2021.1886392] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 02/02/2023] Open
Abstract
Paracetamol (acetaminophen) is undoubtedly one of the most widely used drugs worldwide. As an over-the-counter medication, paracetamol is the standard and first-line treatment for fever and acute pain and is believed to remain so for many years to come. Despite being in clinical use for over a century, the precise mechanism of action of this familiar drug remains a mystery. The oldest and most prevailing theory on the mechanism of analgesic and antipyretic actions of paracetamol relates to the inhibition of CNS cyclooxygenase (COX) enzyme activities, with conflicting views on the COX isoenzyme/variant targeted by paracetamol and on the nature of the molecular interactions with these enzymes. Paracetamol has been proposed to selectively inhibit COX-2 by working as a reducing agent, despite the fact that in vitro screens demonstrate low potency on the inhibition of COX-1 and COX-2. In vivo data from COX-1 transgenic mice suggest that paracetamol works through inhibition of a COX-1 variant enzyme to mediate its analgesic and particularly thermoregulatory actions (antipyresis and hypothermia). A separate line of research provides evidence on potentiation of the descending inhibitory serotonergic pathway to mediate the analgesic action of paracetamol, but with no evidence of binding to serotonergic molecules. AM404 as a metabolite for paracetamol has been proposed to activate the endocannabinoid and the transient receptor potential vanilloid-1 (TRPV1) systems. The current review gives an update and in some cases challenges the different theories on the pharmacology of paracetamol and raises questions on some of the inadequately explored actions of paracetamol. List of Abbreviations: AM404, N-(4-hydroxyphenyl)-arachidonamide; CB1R, Cannabinoid receptor-1; Cmax, Maximum concentration; CNS, Central nervous system; COX, Cyclooxygenase; CSF, Cerebrospinal fluid; ED50, 50% of maximal effective dose; FAAH, Fatty acid amidohydrolase; IC50, 50% of the maximal inhibitor concentration; LPS, Lipopolysaccharide; NSAIDs, Non-steroidal anti-inflammatory drugs; PGE2, Prostaglandin E2; TRPV1, Transient receptor potential vanilloid-1.
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Affiliation(s)
- Samir S Ayoub
- School of Health, Sport and Bioscience, Medicines Research Group, University of East London, London, UK
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7
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Electrocortical Effects of Acetaminophen during Emotional Picture Viewing, Cognitive Control, and Negative Feedback. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2021; 21:390-400. [DOI: 10.3758/s13415-021-00866-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/07/2021] [Indexed: 01/12/2023]
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8
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Barrière DA, Boumezbeur F, Dalmann R, Cadeddu R, Richard D, Pinguet J, Daulhac L, Sarret P, Whittingstall K, Keller M, Mériaux S, Eschalier A, Mallet C. Paracetamol is a centrally acting analgesic using mechanisms located in the periaqueductal grey. Br J Pharmacol 2020; 177:1773-1792. [PMID: 31734950 DOI: 10.1111/bph.14934] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 10/01/2019] [Accepted: 10/24/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE We previously demonstrated that paracetamol has to be metabolised in the brain by fatty acid amide hydrolase enzyme into AM404 (N-(4-hydroxyphenyl)-5Z,8Z,11Z,14Z-eicosatetraenamide) to activate CB1 receptors and TRPV1 channels, which mediate its analgesic effect. However, the brain mechanisms supporting paracetamol-induced analgesia remain unknown. EXPERIMENTAL APPROACH The effects of paracetamol on brain function in Sprague-Dawley rats were determined by functional MRI. Levels of neurotransmitters in the periaqueductal grey (PAG) were measured using in vivo 1 H-NMR and microdialysis. Analgesic effects of paracetamol were assessed by behavioural tests and challenged with different inhibitors, administered systemically or microinjected in the PAG. KEY RESULTS Paracetamol decreased the connectivity of major brain structures involved in pain processing (insula, somatosensory cortex, amygdala, hypothalamus, and the PAG). This effect was particularly prominent in the PAG, where paracetamol, after conversion to AM404, (a) modulated neuronal activity and functional connectivity, (b) promoted GABA and glutamate release, and (c) activated a TRPV1 channel-mGlu5 receptor-PLC-DAGL-CB1 receptor signalling cascade to exert its analgesic effects. CONCLUSIONS AND IMPLICATIONS The elucidation of the mechanism of action of paracetamol as an analgesic paves the way for pharmacological innovations to improve the pharmacopoeia of analgesic agents.
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Affiliation(s)
- David André Barrière
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France.,NeuroSpin, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Romain Dalmann
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
| | - Roberto Cadeddu
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
| | - Damien Richard
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
| | - Jérémy Pinguet
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
| | - Laurence Daulhac
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
| | - Philippe Sarret
- Département de Physiologie et Biophysique/Institut de Pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Kevin Whittingstall
- Département de Radiologie Diagnostique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Matthieu Keller
- UMR Physiologie de la Reproduction et des Comportements, INRA/CNRS/Université de Tours/IFCE, Nouzilly, France
| | | | - Alain Eschalier
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
| | - Christophe Mallet
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Basics and Clinical Pharmacology of Pain, Clermont-Ferrand, France.,Analgesia Institute, Faculty of Medicine, Clermont-Ferrand, France
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9
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Jaswal SM, Granados Samayoa JA, Kam JWY, Randles D, Heine SJ, Handy TC. The Influence of Acetaminophen on Task Related Attention. Front Neurosci 2019; 13:444. [PMID: 31130842 PMCID: PMC6509963 DOI: 10.3389/fnins.2019.00444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 04/17/2019] [Indexed: 11/19/2022] Open
Abstract
Our study was designed to examine whether the pain reliever acetaminophen impacts the normal ebb-and-flow of off-task attentional states, such as captured by the phenomenon of mind wandering. In a placebo-controlled between-groups design, participants performed a sustained attention to response task while event-related potentials (ERPs) to target events were recorded. Participants were queried at random intervals for their attentional reports – either “on-task” or “off-task.” The frequency of these reports and the ERPs generated by the preceding target events were assessed. Behaviorally, the frequency of off-task attentional reports was comparable between groups. Electrophysiologically, two findings emerged: first, the amplitude of the P300 ERP component elicited by target events was significantly attenuated during off-task vs. on-task attentional states in both the acetaminophen and placebo groups. Second, the amplitude of the LPP ERP component elicited by target events showed a significant decrease during off-task attentional states that was specific to the acetaminophen group. Taken together, our findings support the conclusion that acetaminophen doesn’t impact our relative propensity to drift into off-task attentional states, but it does affect the depth of neurocognitive disengagement during off-task attentional states, and in particular, at the level of post-categorization stimulus evaluations indexed by the LPP.
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Affiliation(s)
- Sumeet Mutti Jaswal
- Department of Psychology, The University of British Columbia, Vancouver, BC, Canada
| | | | - Julia W Y Kam
- Department of Psychology, University of California, Berkeley, Berkeley, CA, United States
| | - Daniel Randles
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Steven J Heine
- Department of Psychology, The University of British Columbia, Vancouver, BC, Canada
| | - Todd C Handy
- Department of Psychology, The University of British Columbia, Vancouver, BC, Canada
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10
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Mischkowski D, Crocker J, Way BM. A Social Analgesic? Acetaminophen (Paracetamol) Reduces Positive Empathy. Front Psychol 2019; 10:538. [PMID: 31001155 PMCID: PMC6455058 DOI: 10.3389/fpsyg.2019.00538] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 02/25/2019] [Indexed: 01/10/2023] Open
Abstract
Acetaminophen – a potent physical painkiller that also reduces empathy for other people’s suffering – blunts physical and social pain by reducing activation in brain areas (i.e. anterior insula and anterior cingulate) thought to be related to emotional awareness and motivation. Some neuroimaging research on positive empathy (i.e., the perception and sharing of positive affect in other people) suggests that the experience of positive empathy also recruits these paralimbic cortical brain areas. We thus hypothesized that acetaminophen may also impair affective processes related to the experience of positive empathy. We tested this hypothesis in a double-blind, placebo-controlled experiment. Specifically, we administered 1,000 mg acetaminophen or a placebo and measured effects on different measures of positive empathy while participants read scenarios about the uplifting experiences of other people. Results showed that acetaminophen reduced personal pleasure and other-directed empathic feelings in response to these scenarios. In contrast, effects on perceived positivity of the described experiences or perceived pleasure in scenario protagonists were not significant. These findings suggest that (1) acetaminophen reduces affective reactivity to other people’s positive experiences and (2) the experience of physical pain and positive empathy may have a more similar neurochemical basis than previously assumed. Because the experience of positive empathy is related to prosocial behavior, our findings also raise questions about the societal impact of excessive acetaminophen consumption.
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Affiliation(s)
- Dominik Mischkowski
- Department of Psychology, Ohio University, Athens, OH, United States.,Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, United States
| | - Jennifer Crocker
- Department of Psychology, The Ohio State University, Columbus, OH, United States
| | - Baldwin M Way
- Department of Psychology, The Ohio State University, Columbus, OH, United States.,Institute for Behavioral Medicine Research, The Ohio State University, Columbus, OH, United States
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11
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Pickering G, Creveaux I, Macian N, Pereira B. Paracetamol and Pain Modulation by TRPV1, UGT2B15, SULT1A1 Genotypes: A Randomized Clinical Trial in Healthy Volunteers. PAIN MEDICINE 2019; 21:661-669. [DOI: 10.1093/pm/pnz037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Abstract
Background
The influence of the genetic polymorphism of enzymes and receptors involved in paracetamol metabolism and mechanism of action has not been investigated. This trial in healthy volunteers investigated the link between paracetamol pain relief and the genetic polymorphism of 23 enzymes and receptors.
Design
This randomized double-blind crossover controlled pilot study took place in the Clinical Pharmacology Department, University Hospital, Clermont-Ferrand, France. Forty-seven Caucasian volunteers were recruited. The trial consisted of two randomized sessions one week apart with oral paracetamol or placebo, and pain changes were evaluated with mechanical pain stimuli. The genetic polymorphism of 23 enzymes and receptors was studied, and correlations were made with pain relief. All tests are two-sided with a type I error at 0.05.
Results
Paracetamol was antinociceptive compared with placebo (222 ± 482 kPaxmin vs 23 ± 431 kPaxmin; P = 0.0047), and the study showed 30 paracetamol responders and 17 paracetamol nonresponders. Responders were characterized by TRPV1rs224534 A allele, UGT2B15rs1902023 TT genotype, and SULT1A1rs9282861 GG genotype (P < 0.05 for all). These findings confirm for the first time the involvement of a specific TRPV1 rs224534 variant in paracetamol antinociception. They also reveal a new antinociceptive role for specific variants of hepatic phase II enzymes associated with paracetamol metabolism.
Conclusions
The study warrants larger clinical trials on these potential genomic markers of paracetamol analgesia in patients. Confirmation of the present findings would open the way to effective individualized pain treatment with paracetamol, the most commonly used analgesic worldwide.
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Affiliation(s)
- Gisèle Pickering
- Faculty of Medicine Inserm 1107, Clinical Pharmacology Centre, CPC/CIC Inserm 1405 University Hospital, Clermont-Ferrand, France
| | - Isabelle Creveaux
- Molecular Biology Department, Faculty of Medicine, University Hospital, Clermont-Ferrand, France
| | - Nicolas Macian
- Faculty of Medicine Inserm 1107, Clinical Pharmacology Centre, CPC/CIC Inserm 1405 University Hospital, Clermont-Ferrand, France
| | - Bruno Pereira
- Direction Recherche Clinique, Biostatistics Unit, CHU Clermont-Ferrand, Clermont-Ferrand, France
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12
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Yue Y, Collaku A. Correlation of Pain Reduction with fMRI BOLD Response in Osteoarthritis Patients Treated with Paracetamol: Randomized, Double-Blind, Crossover Clinical Efficacy Study. PAIN MEDICINE 2019; 19:355-367. [PMID: 29025005 PMCID: PMC5914370 DOI: 10.1093/pm/pnx157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Objective To assess the relationship between the analgesic efficacy of extended-release paracetamol (ER-APAP) and brain blood oxygen level–dependent (BOLD) signal activation in response to painful stimulation measured by functional magnetic resonance imaging (fMRI) in patients with osteoarthritis of the knee. Methods This placebo-controlled, double-blind, crossover, randomized trial (N = 25) comprised three treatment periods in which patients received four doses of an eight-hour ER-APAP caplet (2 x 665 mg), four doses of matched placebo, and no treatment. Pain intensity of the knee was measured before and after painful stimulation at the knee with osteoarthritis and before and after fMRI. Results ER-APAP significantly reduced prestimulation osteoarthritis knee joint pain compared with baseline (P < 0.003) and placebo (P < 0.004). ER-APAP and placebo significantly reduced knee joint pain after stimulation (P = 0.014 and P = 0.032, respectively); however, pain reduction with ER-APAP was 35% greater than placebo. ER-APAP was associated with significant reductions in BOLD signal activation after stimulation compared with control in the sensory cortex (P = 0.002) and supramarginal gyrus (P = 0.003). Reduction in BOLD signal activation after stimulation for placebo was significantly greater than control in the subgenual prefrontal cortex (P < 0.001), frontal cortex (P < 0.001), insula (P < 0.003), and sensory cortex (P < 0.001). Conclusions ER-APAP had a significantly greater effect than placebo and no treatment in reducing knee pain, which was associated with reduced BOLD signal activations in pain pathways, including the sensory cortex and supramarginal gyrus. BOLD observations after placebo treatment may shed light on the role of the brain regions potentially involved in placebo response in clinical trials investigating pain therapies.
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Affiliation(s)
- Yong Yue
- GlaxoSmithKline Consumer Healthcare, Warren, New Jersey, USA
| | - Agron Collaku
- GlaxoSmithKline Consumer Healthcare, Warren, New Jersey, USA
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Effet antalgique aigu du paracétamol en soins primaires : des preuves incomplètes. Therapie 2017; 72:609-613. [DOI: 10.1016/j.therap.2017.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 02/16/2017] [Accepted: 02/27/2017] [Indexed: 11/18/2022]
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14
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Analgesics and Sport Performance: Beyond the Pain-Modulating Effects. PM R 2017; 10:72-82. [PMID: 28782695 DOI: 10.1016/j.pmrj.2017.07.068] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/18/2017] [Accepted: 07/25/2017] [Indexed: 11/24/2022]
Abstract
Analgesics are used widely in sport to treat pain and inflammation associated with injury. However, there is growing evidence that some athletes might be taking these substances in an attempt to enhance performance. Although the pharmacologic action of analgesics and their use in treating pain with and without anti-inflammatory effect is well established, their effect on sport performance is debated. The aim of this review was to evaluate the evidence of whether analgesics are capable of enhancing exercise performance and, if so, to what extent. Paracetamol has been suggested to improve endurance and repeated sprint exercise performance by reducing the activation of higher brain structures involved in pain and cognitive/affective processing. Nonsteroidal anti-inflammatory drugs affect both central and peripheral body systems, but investigation on their ergogenic effect on muscle strength development has provided equivocal results. The therapeutic use of glucocorticoids is indubitable, but clear evidence exists for a performance-enhancing effect after short-term oral administration. Based on the evidence presented in this review article, the ergogenic benefit of analgesics may warrant further consideration by regulatory bodies. In contrast to the aforementioned analgesics, there is a paucity of research on the use of opioids such as tramadol on sporting performance. LEVEL OF EVIDENCE III.
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Pickering G, Macian N, Dubray C, Pereira B. Paracetamol sharpens reflection and spatial memory: a double-blind randomized controlled study in healthy volunteers. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:3969-3976. [PMID: 27980393 PMCID: PMC5147402 DOI: 10.2147/dddt.s111590] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Background Acetaminophen (APAP, paracetamol) mechanism for analgesic and antipyretic outcomes has been largely addressed, but APAP action on cognitive function has not been studied in humans. Animal studies have suggested an improved cognitive performance but the link with analgesic and antipyretic modes of action is incomplete. This study aims at exploring cognitive tests in healthy volunteers in the context of antinociception and temperature regulation. A double-blind randomized controlled study (NCT01390467) was carried out from May 30, 2011 to July 12, 2011. Methods Forty healthy volunteers were included and analyzed. Nociceptive thresholds, core temperature (body temperature), and a battery of cognitive tests were recorded before and after oral APAP (2 g) or placebo: Information sampling task for predecisional processing, Stockings of Cambridge for spatial memory, reaction time, delayed matching of sample, and pattern recognition memory tests. Analysis of variance for repeated measures adapted to crossover design was performed and a two-tailed type I error was fixed at 5%. Results APAP improved information sampling task (diminution of the number of errors, latency to open boxes, and increased number of opened boxes; all P<0.05). Spatial planning and working memory initial thinking time were decreased (P=0.04). All other tests were not modified by APAP. APAP had an antinociceptive effect (P<0.01) and body temperature did not change. Conclusion This study shows for the first time that APAP sharpens decision making and planning strategy in healthy volunteers and that cognitive performance and antinociception are independent of APAP effect on thermogenesis. We suggest that cognitive performance mirrors the analgesic rather than thermic cascade of events, with possibly a central role for serotonergic and cannabinoid systems that need to be explored further in the context of pain and cognition.
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Affiliation(s)
- Gisèle Pickering
- University Hospital, CHU Clermont-Ferrand, Centre de Pharmacologie Clinique; Inserm, CIC 1405, UMR Neurodol 1107; Clermont Université, Laboratoire de Pharmacologie, Faculté de médicine
| | - Nicolas Macian
- University Hospital, CHU Clermont-Ferrand, Centre de Pharmacologie Clinique; Inserm, CIC 1405, UMR Neurodol 1107
| | - Claude Dubray
- University Hospital, CHU Clermont-Ferrand, Centre de Pharmacologie Clinique; Inserm, CIC 1405, UMR Neurodol 1107; Clermont Université, Laboratoire de Pharmacologie, Faculté de médicine
| | - Bruno Pereira
- CHU de Clermont-Ferrand, Délégation Recherche Clinique Innovation, Clermont-Ferrand, France
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Zhou SF. Functional magnetic resonance imaging is a powerful approach to probing the mechanism of action of therapeutic drugs that act on the central nervous system. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 9:3863-5. [PMID: 26229446 PMCID: PMC4517517 DOI: 10.2147/dddt.s83038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Shu-Feng Zhou
- Department of Pharmaceutical Science, College of Pharmacy, University of South Florida, Tampa, FL, USA
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