Transcript PHARMACOLOGY OF CHRONIC PAIN MANAGEMENT

PHARMACOLOGY OF
CHRONIC PAIN
MANAGEMENT
April 15, 2011
Michael J. Schwartz, M.D.
Founder & Director
OKLAHOMA PainCare, Inc.
CHRONIC PAIN - CNS
PAIN ROADMAP
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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
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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
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Sensitization of peripheral nociceptors →
↑magnitude and speed
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Hyperalgesia
Activation of low-threshold
mechanreceptors
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Allodynia
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Touch → pain
Central sensitization
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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
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Pain signal outlived its use
Becomes faulty wiring
‘Wind-up’ of the pain signal
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Louder and faster
CNS sub-optimal pain perception &
processing
No longer a healthy pain response
BASICS
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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”
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Pain is the most common reason people seek
medical attention
Pain is a ubiquitous phenomenon
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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
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Pain is a dirty 4-letter word
HONESTY of patient and physician
Weakness
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Avoid responsibilities
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Suck it up; “buck-up”
Work, family dynamics, parenting
Worthless; guilt; ‘no way out’
Importance of Chronic Pain
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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!
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Approximately ≥ $100 billion per year including
medical expenses, lost wages, and decreased
productivity
TYPES OF PAIN
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Acute nociceptive
Inflammatory/joint
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Visceral nociceptive
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Hypersensitive response to tissue damage and
inflammation
IBS; IBD; IC; Crohn’s; endometriosis; etc
Neuropathic
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Constant alarm without emergency, maladaptive,
spontaneous, flunctuating
DPN; vascular neuropathy; TGN; PHN; etc
Medical Management of
Chronic Pain
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Pain coaching
Life counseling
CBT; ACT
Pain psychologist
Sleep evaluation
Rehabilitation
Interventional
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Blocks
SCS; IT pump
Neurolytic procedures
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Pharmacology
 Opioid
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Non-opioid adjuvants
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SMRs; AEDs;
SNRIs; SSRIs;
NSAIDs (nonselective COX-I
and selective
COX-II;
anxiolytics;
hypnotics;
dopaminergics;
etc
Pharmacologic options
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Opioids
Non-opioid adjuvants:
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Antidepressants (SNRIs & SSRIs)
Anticonvulsants (AEDs)
NSAIDs,
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non-selective COX-I
selective COX-II
Local anesthetics
SMRs
-adrenergic agents
Topical agents
DEFINITIONS
Physical dependence: normal adaptation to a
drug-class
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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
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‘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
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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
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Opioids
Non-opioid adjuvants
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Antidepressants (SNRIs & SSRIs)
Anticonvulsants (AEDs)
NSAIDs
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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
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QT interval
Dosing:
 Q 6hr optimal – strict schedule
OPIOID POLICIES
Federal laws
 State laws
 Regulatory guidelines
 Policy statements
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MANAGING CHRONIC PAIN
WITH OPIOIDS
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Patient selection
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One size does not fit all
Risk stratification
Informed consent and opioid
management plan
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Goals of treatment
Expectations
Risks and alternatives
MANAGING CHRONIC PAIN
WITH OPIOIDS
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Monitoring patients:
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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
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Monitoring patients:
4 As
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Analgesia
ADLs - level of function, progress towards
goals
Adverse events – ASEs, CSEs
Aberrant medication use - compliance
PATIENT ASSESSMENT FOR
OPIOID THERAPY
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Chief complaint
Pain history
Pain medication history
Past history
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Including psychiatric hx and substance use &
abuse hx
Social history
Family history
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Including psychiatric hx and substance use &
abuse hx
PATIENT ASSESSMENT FOR
OPIOID THERAPY
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Physical examination
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Features relevant to pain and substance use
Additional information:
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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
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Opioid Risk Test (ORT)
Screener and Opioid Assessment for
Patient with Pain (SOAPP)
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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
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Methadone different animal
Propoxyphene off market
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Reduce amount by ≥ 50%
FDA banned in Feb 2011
Meperidine not for chronic pain management
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“Demerol blizzard”
Defects in Opioid Metabolism
Genetic screening
 Cytochrome 450 (CYP 450)
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CYP 2D6; CYP 2C9
Most common defect CYP 3A4
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Testing not available
Why?
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Avoid drug interactions (ADRs)
High-dose opioids
Unusual or expensive regimen
Defects in Opioid Metabolism
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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
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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
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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.
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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
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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.
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OKLAHOMA PainCare, Inc.
[email protected]
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