Transcript of "Current Concepts and Strategies in Pain Management"
Current Concepts and Strategies in Pain Management Raymond G. Tatevossian, MD Chair, Pain &Palliative Care Committee, PSJMC Clinical Assistant Professor of Anesthesiology, USC Keck School Medicine
Lecture Objectives• Current Understanding Of Pain Mechanisms• Current Treatment Strategies• Medication Update• Controversies Surrounding Opioids• Prudent Opioid Prescribing• Advanced Interventional Techniques
Pain: The Statistics• 2nd leading cause of medically related lost work days• $100 billion/year cost to US economy• 42% adults experience daily pain• 50% of population see a doctor with “Pain” as the chief complaint• 66% of US veterans report persistent pain attributable to military service
Is All Pain “Bad?”The Gift of Pain by Dr. Paul Brand• “The Beloved Enemy”• Pain is evolutionarily necessary for survival – Acute pain is protective
The “Gift” of Pain--an Example• Mycobacterium leprae – Disfigurement • Infectious processes or painlessness?• The Cat Test – Sensory Neuropathy http://bhavanajagat.files.wordpress.com/
Classification of PainAcute Chronic• Generally protective • Generally no useful fnctn.• Relieved when healing • Persists after healing complete complete• Short duration • Long duration• Predictable pathology • Unpredictable Pathology• Predictable prognosis • Unpredictable prognosis• Tx with analgesics • Tx multidisciplinary
Factors Contributing to Chronic Pain“Chronic Pain Load”• Intensity of injury• Duration of injury• Repetitiveness of injury• Chronicity of underlying disease• Genetic predisposition – BH4 enzyme production• Other factors: - Psychological - Socioeconomic - Cultural
Mechanisms of Pain: Neuroplasticity How does a Chronic Pain State Develop?• Peripheral Sensitization- Injury causes release of “sensitizing soup”- Reduction in threshold and increase response of nocioceptors• Central Sensitization- Membrane excitability, synaptic recruitment and decreased inhibition- Uncoupling of pain from peripheral stimuli http://www.aafp.org/afp/2001
Goals of Treatment• Reduce pain• Increase activity level• Improve quality of life• Pre-emptive analgesia• Stay within “Therapeutic Window” – Avoid undertreatment – Avoid toxicity• How? – Synergism with Meds • Morphine + Gabapentin – Apply multimodal pain strategies when possible
Analgesic Medication UpdateFDA Advisory Panel Recs/Trends:• Acetaminophen- ↓ max daily dose, ↓ max single dose• Vicodin, Percocet - ban in current form• Propoxyphene (Darvocet)- push for phased withdrawalAbuse Deterrent Opioids:• Morphine ER+ Naltrexone (Embeda)• Oxycodone IR+ Naltrexone (Oxytrex)• Oxycodone IR + Niacin (Acurox)
Emerging Analgesic Medications• IV Acetaminophen (Paracetamol) – opioid sparring, phase 3 completed• Tapendatol (Nucynta) µ-opioid agonist, NE reuptake inhibitor ↓ GI effects, ER phase 3• Hydromorphone Extended Release (Exalgo) – FDA approved 3/1/2010, awaiting REMS
Opioids--The Evolving ControversyPast: Decreased Scrutiny• 1990: Pain becomes “fifth vital sign”• 1990: Intractable Pain Act – “no physician or surgeon shall be subject to disciplinary action … for prescribing controlled substances for intractable pain”• Medical Board CA defines under treatment of pain as “inappropriate prescribing”• Bergman vs Chin: $ 1.5 million dollars awarded for under treatment of pain• 2000-2005 a 35-50% increase in opioid prescribing
Opioids--The Evolving ControversyPresent: Increased Scrutiny• Most common class of medication prescribed – 800% increase in 10 years• Fatal opioid poisonings have tripled 1999-2006• Food & Drug Administration Act (2007) – Creation of REMS for new and existing drugs• McLellan and Turner, Annals On Internal, Editorial, Jan 2010- “prescribing opioids at high doses is both dangerous amd questionable”- White House Office of National Drug Control Policy
Strategic Opioid PrescribingPrescription Monitoring Opioid Contract• CURES (CA) • Call it “Opioid Consent”• Pharmacists, physicians, • Discuss risks and and law enforcement benefits of opioids officials • Educational• Real time, S II – IV • Establish rules of• https://pmp.doj.ca.gov/pm prescribing preg
Intrathecal Drug Delivery SystemsAKA: Pain pumpMechanism of Action:• Drug delivered directly to the intrathecal spaceDrugs:• Morphine• Baclofen• Ziconotide (Prialt®) http://www.medtronic.com/IN/images/intro_intrathecal1.gif• Bupivicaine• Clonidine• Ketamine
Intrathecal Drug Delivery SystemsPROS CONS• Short reversible trial • Short reversible trial• Delivery of drug ∀ ↓opioid benefit with directly to the site of time (40% failure with action time)• 1mg IT Morphine = • Contraindications to 300 gm oral Morphine placement• Cancer Pain: ↓pain, • Complications ↓toxicity, ↑survival (granuloma) 6mo
Spinal Cord Stimulation• Production of electrical field over dorsal columns by epidurally placed electrodes• Gate Control Theory – Gate exists in dorsal horn that governs pain signal transmission – Closing gate decreases pain• Parasthesia produced over painful body area
Spinal Cord StimulationGrade A Evidence• Failed Back Surgery• ArachnoiditisGrade B Evidence• CRPS I• CRPS IIOther Indications• Phantom limb, post herpetic neuralgia, spinal cord injury www.medscape.com
References1. Arthritis Foundation. (2000) Pain in America. http://www.arthritisfoundation.org2. American Pain Foundation. http://www.painfoundation.org.3. National Institutes of Health. NIH Guide: New Directions in Pain Research: Bethsea.1998.4. Brand P and Yancey P. The Gift of Pain. Michigan: Zondervan Publishing House, 1997.5. Turk D. Pain Hurts-Individuals, Significant Others, and Society. APS Bulletin. 2006;16:1.6. Payne J. Pain medications: What you need to know about acetaminophen, darvon, and darvocet. US News and World Report 2009.7. Jamison R and Clark D. Opioid Medication Management:Clinician beware. Anesthesiology 2010; 112:777-8.8. Tucker K. Promoting good pain management in california. California Health Law News 2004;22:1-4.9. McLellan T. Chronic noncancer pain management and opioid overdose: Time to change prescribing practices. Annals of Internal Medicine 2010;152:123-4.10. http://cdc.gov/nchs/data/databriefs/db22.htm11. http://www.painmed.org/pdf/rems_comments.pdf12. Cousins M, Carr D, et al. Neural blockade in clinical anesthesia and pain medicine. New York: LWW, 2009.13. American Society of Anesthesiologists Task Force on Chronic Pain Management. Practice guidelines for chronic pain management: an updated report by the ASA. Anesthesiology 2010;112:810-33.14. Gilron I, Bailey J, et al. Morphine, gabapentin, or their combination for neuropathic pain. NEJM 2005;352:1324-34.15. Smith T, Staats P, et al. Randomized clinical trial of an implantable drug delivery system compared with comprehensive medical management for refractory cancer pain:impact on pain, drug-related toxicity, and survival. J of Clinical Oncology. 2002;20:4040-9.16. Barolat G, Massaro F, et al. Mapping of sensory responses to epidural stimulation of the intraspinal neural structures in man. J. Neurosurg 1993;78:233-239.
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