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PHARMACOLOGY OF CHRONIC PAIN MANAGEMENT April 15, 2011 Michael J. Schwartz, M.D. Founder & Director OKLAHOMA PainCare, Inc. CHRONIC PAIN - CNS PAIN ROADMAP Noxious stimulus in periphery transduced into electrical activity Bidirectional process with both ascending and descending inputs Normal response is protective and adaptive Persistent pain → maladaptive Neuroplastic changes that affect pain perception Ultimately pain sensations out of proportion CHRONIC PAIN - CNS Acute vs Chronic Pain Pain-Sensing System Malfunction in Chronic Pain Normal Pain Pain-sensing signals are initiated in response to a stimulus They elicit a pain-relieving response Chronic Pain Pain signals are generated for no reason and may be intensified Pain-relieving mechanisms may be defective or deactivated Pain-Sensing System Malfunction in Chronic Pain Sensitization of peripheral nociceptors → ↑magnitude and speed Hyperalgesia Activation of low-threshold mechanreceptors Allodynia Touch → pain Central sensitization Loss of inhibitory effects of myelinated primary afferents Reorganization of spinal cord connections after deafferentation Spontaneous activity in deafferented spinal pain transmission neurons Prolonged excitation or sensitization of spinal pain transmission neurons CHRONIC PAIN Pain Sensing Pain signals are generated without physiologic significance CHRONIC PAIN Pain signal outlived its use Becomes faulty wiring ‘Wind-up’ of the pain signal Louder and faster CNS sub-optimal pain perception & processing No longer a healthy pain response BASICS The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage” Pain is the most common reason people seek medical attention Pain is a ubiquitous phenomenon The same set of circumstances can cause significant pain in one patient, and little or none in another Pain is both a sensory and an emotional experience HOUSE of PAIN Pain is a dirty 4-letter word HONESTY of patient and physician Weakness Avoid responsibilities Suck it up; “buck-up” Work, family dynamics, parenting Worthless; guilt; ‘no way out’ Importance of Chronic Pain When improperly managed, pain can lead to decreased productivity and diminished quality of life Estimates show that chronic pain affects approximately 90 million Americans each year The burden placed on our society in financial terms is tremendous! Approximately ≥ $100 billion per year including medical expenses, lost wages, and decreased productivity TYPES OF PAIN Acute nociceptive Inflammatory/joint Visceral nociceptive Hypersensitive response to tissue damage and inflammation IBS; IBD; IC; Crohn’s; endometriosis; etc Neuropathic Constant alarm without emergency, maladaptive, spontaneous, flunctuating DPN; vascular neuropathy; TGN; PHN; etc Medical Management of Chronic Pain Pain coaching Life counseling CBT; ACT Pain psychologist Sleep evaluation Rehabilitation Interventional Blocks SCS; IT pump Neurolytic procedures Pharmacology Opioid Non-opioid adjuvants SMRs; AEDs; SNRIs; SSRIs; NSAIDs (nonselective COX-I and selective COX-II; anxiolytics; hypnotics; dopaminergics; etc Pharmacologic options Opioids Non-opioid adjuvants: Antidepressants (SNRIs & SSRIs) Anticonvulsants (AEDs) NSAIDs, non-selective COX-I selective COX-II Local anesthetics SMRs -adrenergic agents Topical agents DEFINITIONS Physical dependence: normal adaptation to a drug-class Abrupt cessation, rapid↓dose, antagonist, etc → withdrawal syndrome Tolerance: drug exposure → ↓effect over time Addiction: primary, chronic, neurobiologic DZ with genetic, psychosocial & environmental influences DEFINITIONS Addiction behaviors: Impaired control over drug use Compulsive use Continued use despite harm Craving ‘Mad, sad or glad’ DEFINITIONS Abuse: Illegal drug use Self-administration of meds for nonmedical purpose Altered state of consciousness ‘Getting high’ Go to Disney World without leaving the couch DEFINITIONS Aberrant drug-use behavior: Outside the boundaries of the agreed upon treatment plan established in the patientphysician relationship Misuse: Use of medication for medical purpose other than as directed or as indicated, whether willful or unintentional, and whether harm results or not DEFINITIONS Diversion: Intentional transfer of a Controlled Dangerous Substance (CDS) medication for illegitimate use Sell, trade, give, take, etc HOUSE of PAIN Pain patients practice to be worse Pain Brain Chronic pain circle MOOD PAIN SLEEP GOALS of the pharmacologic management of chronic pain Optimally contain the daily chronic pain Improved quality of life (QOL) Improved function physically and emotionally Fewest adverse side effects (ASEs) Fewest cognitive side effects (CSEs) Pharmacologic options Opioids Non-opioid adjuvants Antidepressants (SNRIs & SSRIs) Anticonvulsants (AEDs) NSAIDs Non-selective COX-I Selective COX-II Local anesthetics SMRs -adrenergic agents Topical agents OPIOIDS for daily use Extended-release preferred Morphine Oxycodone Oxymorphine Hydroxymorphine Fentanyl Buprenorphine Immediate-release shortacting opioids (IRSAOs) AVOID daily use of repetitive doses Increased need for dosage escalation Increased risk of true addiction Increased risk of cognitive and motor impairment APAP combo meds → liver & renal toxicity Long-acting opioid (LAO) Methadone Unique characteristics CAUTION! For use only by clinicians familiar with its use and risks A leading cause of inadvertent and accidental overdose and death Methadone Must monitor: K⁺, Na⁺⁺, Mg⁺⁺ EKG QT interval Dosing: Q 6hr optimal – strict schedule OPIOID POLICIES Federal laws State laws Regulatory guidelines Policy statements MANAGING CHRONIC PAIN WITH OPIOIDS Patient selection One size does not fit all Risk stratification Informed consent and opioid management plan Goals of treatment Expectations Risks and alternatives MANAGING CHRONIC PAIN WITH OPIOIDS Monitoring patients: Level of function Progress towards goals Presence of adverse events Compliance Psychotherapeutic co-interventions Driving and work safety Breakthrough pain Exit strategy MANAGING CHRONIC PAIN WITH OPIOIDS Monitoring patients: 4 As Analgesia ADLs - level of function, progress towards goals Adverse events – ASEs, CSEs Aberrant medication use - compliance PATIENT ASSESSMENT FOR OPIOID THERAPY Chief complaint Pain history Pain medication history Past history Including psychiatric hx and substance use & abuse hx Social history Family history Including psychiatric hx and substance use & abuse hx PATIENT ASSESSMENT FOR OPIOID THERAPY Physical examination Features relevant to pain and substance use Additional information: Urine and/or serum drug test monitoring Screening for risk of substance use or aberrant medication-use behavior Outside medical records Prescription monitoring reports (OBN PMP) OPIOID RISK ASSESSMENT Opioid Risk Test (ORT) Screener and Opioid Assessment for Patient with Pain (SOAPP) SOAPP-14, SOAPP-24, SOAPP-R (revised) Current Opioid Misuse Measure (COMM) Zung, HAM-D, HAM-A, etc Other non-opioid eg. Epworth Aberrant Drug-Taking Behaviors Probably more predictive: Selling scripts Prescription forgery Stealing or borrowing meds Obtaining scripts from nonmedical sources Concurrent abuse of related illicit meds Multiple unsanctioned dose escalations Recurrent script or med losses Aberrant Drug-Taking Behaviors Probably less predictive: Aggressive complaining about pain intensity and need for higher doses Drug hoarding Requesting specific medications Obtaining CDS meds from other medical source Unsanctioned dose escalation 1-2 times Use of med to tx other symptoms Reporting psychic effects of meds Opioid conversions Equianalgesic dose calculations of different opioids Methadone different animal Propoxyphene off market Reduce amount by ≥ 50% FDA banned in Feb 2011 Meperidine not for chronic pain management “Demerol blizzard” Defects in Opioid Metabolism Genetic screening Cytochrome 450 (CYP 450) CYP 2D6; CYP 2C9 Most common defect CYP 3A4 Testing not available Why? Avoid drug interactions (ADRs) High-dose opioids Unusual or expensive regimen Defects in Opioid Metabolism Suspect genetic metabolic defect if when opioid blood levels are very high or very low Screening costly Insurance says “experimental” Exit Strategy for discontinuing opioid therapy Opioid risk-benefit ratio Intolerable side effects Opioid rotation failure Deterioration of QOL Poor compliance Aberrant med-use behavior PPP – mean disagreeable pts Chronic Pain Resources American Academy of Pain Management http://www.aapainmanage.org/ - The American Academy of Pain Management is a non-profit organization that educates clinicians about pain and its management through an integrative interdisciplinary approach. American Academy of Pain Medicine http://www.painmed.org/ - The American Academy of Pain Medicine (AAPM) is the medical specialty society representing physicians practicing in the field of Pain Medicine American Chronic Pain Association http://www.theacpa.org/ - To facilitate peer support and education for individuals with chronic pain and their families so that these individuals may live more fully in spite of their pain. American Pain Foundation http://www.painfoundation.org/ - NPO site that contains newsletter, downloadable patient resources (MS Word), and discussion boards. American Pain Society (APS) http://www.ampainsoc.org/ - Multidisciplinary, scientific and professional society. Contains announcements of positions, fellowships, grants, etc. American Society for Action on Pain http://www.druglibrary.org/schaffer/asap/ - Patient organization interested in pain management issues/concerns. American Society for Pain Management Nursing http://www.aspmn.org/ - Organization of professional nurses that provide support to pain management. Contains announcements and an e-mail list. American Society of Addiction Medicine http://www.asam.org/ - Site dedicated to increasing the quality of addiction treatment. Includes certification, publications, and conference info. American Society of Regional Anesthesia and Pain Medicine http://www.asra.com/ - Member info, web-based CME, and fellowship opportunities are some of the highlights. Drugs4Real http://www.drugs4real.com/ - An interactive prevention program that teaches adolescents about the influence of alcohol and drugs and strengthens their commitment to avoid taking these substances. International Association for the Study of Pain (IASP) http://www.iasp-pain.org/ - NPO consisting of health professionals. Access to web-based learning, grants/awards, opportunities, etc. National Pain Foundation http://www.painconnection.org/ - A non-profit organization that provides education and support resources for people in chronic pain, their families, and physicians. Pain & Policy Studies Group, University of Wisconsin http://www.painpolicy.wisc.edu/ - The Pain & Policies Studies Group website contains a wealth of information about pain relief and public policy, both domestic and international. Pain Medicine News http://www.painedu.org/www.painmedicinenews.com - Pain Medicine News has timely frequently updated content designed to meet the needs of the spectrum of physicians involved in pain medicine. Pain Treatment Topics http://www.pain-topics.org/ - With pharmaceutical company support, a noncommercial resource for healthcare professionals, providing clinical news, information, research, and education for a better understanding of evidence-based pain-management practices. Pain.com http://www.pain.com/ - Free web-based CME, articles, and pain journals (all free to view). PainACTION http://www.painaction.com/ - An online self-management program for pain patients, featuring individually-customized information, interactive skill-building tools, monthly newsletter and opportunities to share self-management tips. PainLink http://www.edc.org/PainLink/ - Archived website that still contains applicable information. The Mayday Fund http://www.painandhealth.org/ - Extensive listing of internet resources relating to pain and pain management. Wisconsin Pain Initiative http://www.wisc.edu/wcpi - Grassroots organization of professionals that includes: pain management laws (WI), patient/public/professional education. OPIOIDOLOGY Universal Precautions for Opioid Pain Management Federation of State Medical Licensure Boards Guidelines of American Pain Society & American Academy of Pain Medicine PHARMACOLOGY Michael J. Schwartz, M.D. OKLAHOMA PainCare, Inc. [email protected] Opinions are like rear-ends – we’ve all got one – “and now I’ve shown you mine”