new concepts in pain management
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New Concepts in Pain Management. Melanie Christina, M.D. Presbyterian Hospital Dallas Medical Director, Heartland Hospice. Definition : Pain. An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage - PowerPoint PPT PresentationTRANSCRIPT
New Concepts New Concepts in Painin Pain
ManagementManagement
Melanie Christina, M.D.Melanie Christina, M.D.
Presbyterian Hospital DallasPresbyterian Hospital Dallas
Medical Director, Heartland Medical Director, Heartland HospiceHospice
INTERNATIONAL ASSOCIATION FOR THE STUDY OF PAIN
DefinitionDefinition: Pain: Pain An unpleasant sensory and An unpleasant sensory and
emotional experience associated emotional experience associated with actual or potential tissue with actual or potential tissue damage, or described in terms of damage, or described in terms of such damagesuch damage
Pain is subjective. There is no Pain is subjective. There is no neurophysiological or chemical test neurophysiological or chemical test that can measure pain.that can measure pain.
Prevalence of PainPrevalence of Pain Over 30 million Americans suffer Over 30 million Americans suffer
from chronic nonmalignant painfrom chronic nonmalignant pain 20-30% of the American public 20-30% of the American public
suffer from acute or chronic painsuffer from acute or chronic pain Over 70% of patients with Over 70% of patients with
advanced cancer report having advanced cancer report having moderate to severe painmoderate to severe pain
Barriers in the treatment Barriers in the treatment of Painof Pain
Inadequate assessmentInadequate assessment Specific populations more likely Specific populations more likely notnot to be to be
treatedtreated Patient’s reluctance to report painPatient’s reluctance to report pain Patient’s reluctance to take opioidsPatient’s reluctance to take opioids Doctor’s reluctance to prescribe opioidsDoctor’s reluctance to prescribe opioids
– Fear of regulatory scrutinyFear of regulatory scrutiny– Fear of causing addictionFear of causing addiction– Lack of knowledge regarding dosing and side effects Lack of knowledge regarding dosing and side effects
Important concepts to Important concepts to UnderstandUnderstand AddictionAddiction
– Psychological dependence on substances for their psychic effects and is Psychological dependence on substances for their psychic effects and is characterized by compulsive use despite harm.characterized by compulsive use despite harm.
Analgesic ToleranceAnalgesic Tolerance– The need to increase the dose of opioid to achieve the same level of The need to increase the dose of opioid to achieve the same level of
analgesia.analgesia.
Physical DependencePhysical Dependence– A physiologic state of neuroadaptation which is characterized by the A physiologic state of neuroadaptation which is characterized by the
emergence of a withdrawal syndrome if drug use is stopped or decreased emergence of a withdrawal syndrome if drug use is stopped or decreased abruptly, or if an antagonist is administered.abruptly, or if an antagonist is administered.
PseudoaddictionPseudoaddiction– Pattern of drug-seeking behavior of pain patients who are receiving Pattern of drug-seeking behavior of pain patients who are receiving
inadequate pain medication. Behavior is mistaken for addiction.inadequate pain medication. Behavior is mistaken for addiction.
Guidelines for the Guidelines for the management and treatment management and treatment
of Painof Pain WHO - global initiative on pain WHO - global initiative on pain
management (1986)management (1986) Texas State Board of Medical Examiners Texas State Board of Medical Examiners
(1993)(1993) Federation of State Boards (1998)Federation of State Boards (1998) JCAHO (1999)JCAHO (1999) Governmental guidelines (AHCPR)Governmental guidelines (AHCPR) American Pain SocietyAmerican Pain Society
and many more!!!!!!and many more!!!!!!
Texas State Board of Texas State Board of Medical Examiners’ Medical Examiners’
PositionPosition ““Quality medical practice dictates that those Quality medical practice dictates that those
citizens of TX who suffer pain and other citizens of TX who suffer pain and other distressing symptoms should be adequately distressing symptoms should be adequately relieved so that their quality of life is as relieved so that their quality of life is as optimum as can be.”optimum as can be.”
““The TSBME recognizes that opioids and other The TSBME recognizes that opioids and other Scheduled Controlled substances, are Scheduled Controlled substances, are indispensable for the treatment of pain…”indispensable for the treatment of pain…”
““It is the position of the board that these drugs It is the position of the board that these drugs be prescribed for the treatment of these be prescribed for the treatment of these symptoms in appropriate and adequate doses…” symptoms in appropriate and adequate doses…”
Texas State Board of Texas State Board of Medical Examiners’ Medical Examiners’
PositionPosition
““The Board recognizes that pain, and many The Board recognizes that pain, and many other symptoms are other symptoms are subjective complaintssubjective complaints and appropriateness and adequacy of drug and appropriateness and adequacy of drug and dose will vary from individual to and dose will vary from individual to individual.”individual.”
““The standard will be determined largely by The standard will be determined largely by treatment outcome…”treatment outcome…”
Physicians should be diligent in preventing Physicians should be diligent in preventing (controlled substances) from being diverted (controlled substances) from being diverted from legitimate to illegitimate use.from legitimate to illegitimate use.
Standards used by Board when Standards used by Board when evaluating use of Controlled evaluating use of Controlled
substances:substances: DOCUMENTATIONDOCUMENTATION--Medical records should include:Medical records should include:
– medical history and physicalmedical history and physical– diagnostic, therapeutic and laboratory resultsdiagnostic, therapeutic and laboratory results– evaluations and consultationsevaluations and consultations– treatment objectivestreatment objectives– discussion of risks and benefitsdiscussion of risks and benefits– treatmentstreatments– medication (date, type, dosage, quantity)medication (date, type, dosage, quantity)– instructions and agreementsinstructions and agreements– periodic reviewperiodic review
Joint Commission Joint Commission Standards on Pain Standards on Pain
ManagementManagement
Patient’s have a right to appropriate Patient’s have a right to appropriate assessment and management of painassessment and management of pain
Pain needs to be assessed, documented and Pain needs to be assessed, documented and followed for appropriate interventionsfollowed for appropriate interventions
Policies and procedures should support the Policies and procedures should support the appropriate use of pain medicationsappropriate use of pain medications
Patients and their families should be Patients and their families should be educated on pain managementeducated on pain management
Discharge planning should include symptom Discharge planning should include symptom managementmanagement
Governmental GuidelinesGovernmental Guidelineswww.guidelines.govwww.guidelines.gov
1995 - “Clinical practice guidelines for chronic non-1995 - “Clinical practice guidelines for chronic non-malignant pain syndrome”malignant pain syndrome”
1998 - “The management of persistent pain in 1998 - “The management of persistent pain in older persons”older persons”
1999 - “Procedure guideline for bone treatment 1999 - “Procedure guideline for bone treatment pain”pain”
2000 - “Control of pain in patients with cancer. A 2000 - “Control of pain in patients with cancer. A national clinical guideline”national clinical guideline”
2002 - “Clinical practice guideline for the diagnosis, 2002 - “Clinical practice guideline for the diagnosis, treatment and management of reflex sympathetic treatment and management of reflex sympathetic dystrophy/complex regional pain syndrome”dystrophy/complex regional pain syndrome”
Current Legal Climate -Current Legal Climate -Undertreatment of PainUndertreatment of Pain
Landmark case in California with a Landmark case in California with a family suing the doctor for family suing the doctor for
inadequate pain control in their inadequate pain control in their dying, 85 year old father during dying, 85 year old father during the last week of his life. Jury trial the last week of his life. Jury trial
awarded family 1.5 million awarded family 1.5 million claiming the physicians lack of claiming the physicians lack of attention to pain was “reckless attention to pain was “reckless
negligence” and constituted elder negligence” and constituted elder abuse.abuse.
Tips for Physicians to protect Tips for Physicians to protect themselves from charges of themselves from charges of
Undertreatment of pain:Undertreatment of pain: Review your practice against JCAHO Review your practice against JCAHO
standardsstandards Improve knowledge in pain assessment and Improve knowledge in pain assessment and
treatmenttreatment Utilize local consultation resourcesUtilize local consultation resources Improve knowledge and skills in assessing Improve knowledge and skills in assessing
substance abuse; utilize local resources for substance abuse; utilize local resources for substance abuse referrals and treatmentsubstance abuse referrals and treatment
TYPES OF PAINTYPES OF PAINPathophysiologic categorizationPathophysiologic categorization
NOCICEPTIVENOCICEPTIVE– SOMATICSOMATIC
Stimulation of the somatic Stimulation of the somatic nervous systemnervous system
skin, soft tissue, muscle, skin, soft tissue, muscle, bonebone
easily localizedeasily localized
– VISCERALVISCERAL stimulation of the stimulation of the
autonomic nervous systemautonomic nervous system GI and GU tracts, cardiac, GI and GU tracts, cardiac,
lunglung difficult to describe and difficult to describe and
localizelocalize
NEUROPATHICNEUROPATHIC– PERIPHERAL PERIPHERAL
PROCESSES PROCESSES (neuroma)(neuroma)
– CNS PROCESSES CNS PROCESSES (phantom pain)(phantom pain)
– COMPLEX COMPLEX REGIONAL PAINREGIONAL PAIN
Classification of Classification of PainPain
Based on clinical courseBased on clinical course
Acute painAcute painChronic pain (non-Chronic pain (non-cancer)cancer)
Cancer painCancer painPost-surgical painPost-surgical pain
AHCPR 1994
Assessment of PainAssessment of Pain“ABCDE” Mnemonic“ABCDE” Mnemonic
AAsk about pain regularly; sk about pain regularly; AAssess pain ssess pain systematicallysystematically
BBelieve the patient and family in their reports elieve the patient and family in their reports of pain and what relieves itof pain and what relieves it
CChoose pain control options appropriate for hoose pain control options appropriate for the patient, family and settingthe patient, family and setting
DDeliver interventions in a timely, logical and eliver interventions in a timely, logical and coordinated fashioncoordinated fashion
EEmpower patients and their families; mpower patients and their families; EEnable nable them to control their course to the greatest them to control their course to the greatest extent possibleextent possible
Describing Pain:Describing Pain:“PQRST” Mnemonic“PQRST” Mnemonic
PProvoking or rovoking or PPalliative alliative factorsfactors
QQuality of painuality of pain RRadiationadiation SSeverityeverity TTemporalemporal
Goals in the treatment Goals in the treatment of painof pain
Improve quality of lifeImprove quality of life Encourage mobilityEncourage mobility Reduce hospitalizations and ER Reduce hospitalizations and ER
admissionsadmissions Improve job performanceImprove job performance Impact function in a family unitImpact function in a family unit Prevent depression/suicidePrevent depression/suicide
AspirinAcetaminophen
Nonsteroidal anti-inflammatory drugs+ Adjuvants
MorphineHydromorphone
MethadoneFentanyl
Oxycodone+ Nonopioid analgesics
+ Adjuvants
Step 1, Mild Pain
Step 2, Moderate Pain
Combination opioidsTramadol+ Adjuvants
Step 3, Severe Pain
WHO 3-STEP LADDER
Utilization of Opioids:Utilization of Opioids:Chronic PainChronic Pain
Dose around the clock - achieve blood Dose around the clock - achieve blood levels in the therapeutic range and avoid levels in the therapeutic range and avoid blood levels falling below pain thresholdblood levels falling below pain threshold
Rescue dosing - 10% of total 24 hour Rescue dosing - 10% of total 24 hour dosedose
Dose titration: Dose titration: – mild pain: increase dose by 10%mild pain: increase dose by 10%– moderate pain: increase dose by 25-50%moderate pain: increase dose by 25-50%– severe pain: increase dose by 100%severe pain: increase dose by 100%
Routes of Routes of AdministrationAdministration
Oral - preferredOral - preferred Buccal/sublingualBuccal/sublingual RectalRectal TransdermalTransdermal SubcutaneousSubcutaneous IntravenousIntravenous Intramuscular - CONTRAINDICATEDIntramuscular - CONTRAINDICATED IntrathecalIntrathecal
Equianalgesic Conversion Equianalgesic Conversion TableTable
ANALGESIC ORAL DOSE PARENTERALDOSE
DURATIONOF ACTION(HOURS)
HALF-LIFE(HOURS)
ORAL:PARENTERALRATIO
POMORPHINE:ANALGESICRATIO
Morphine 30mg 10mg 4-6hr 2-4hr 3:1 1:1Oxycodone 20mg 3-5hr 4-5hr 1.5:1Hydro-morphone 7.5mg 1.5mg 3-4hr 2-3hr 5:1 4:1Methadone 20mg 10mg 4-6hr 15-50h 2:1 3:1Codeine 200mg 130mg 4-6hr 3hr 1.5:1 1:7Hydro-codone 30mg 3-6 hr 3-4hr 1:1Meperidine 300mg 75mg 2-4hr 2-3hr 4:1 1:10
Variables in ConsideringVariables in ConsideringEquianalgesic DosesEquianalgesic Doses
Pain intensityPain intensity Prior opioid exposurePrior opioid exposure Incomplete cross toleranceIncomplete cross tolerance Age of PatientAge of Patient Route of administrationRoute of administration Level of ConsciousnessLevel of Consciousness Preexisting conditionsPreexisting conditions
Common Side Effects and Common Side Effects and treatmentstreatments
Constipation - All patients on opioids Constipation - All patients on opioids need a regular bowel program.need a regular bowel program.
Nausea - quickly develop tolerance to thisNausea - quickly develop tolerance to this Pruritus - may need to switch opioidsPruritus - may need to switch opioids Sedation - if tolerance doesn’t occur can Sedation - if tolerance doesn’t occur can
use stimulantsuse stimulants Respiratory depression - most feared yet Respiratory depression - most feared yet
rare side effect if proper dosing followedrare side effect if proper dosing followed
Fear of Respiratory Fear of Respiratory Depression from Opioid Depression from Opioid
UseUse
Patients develop tolerance to the respiratory Patients develop tolerance to the respiratory depressant effects early in course of therapydepressant effects early in course of therapy
Patients with COPD have been shown to Patients with COPD have been shown to experience improvement in exercise experience improvement in exercise tolerance and decreased SOB tolerance and decreased SOB
Terminally ill patients required 1.5-2.5 times Terminally ill patients required 1.5-2.5 times their regular dose of analgesia to control their regular dose of analgesia to control breathlessness; without effect on O2 breathlessness; without effect on O2 saturation or respiratory rate saturation or respiratory rate Annals Internal Medicine 119: 906, 1993Annals Internal Medicine 119: 906, 1993
Fentanyl Transdermal Fentanyl Transdermal SystemSystem
Medication is absorbed into the subcutaneous tissue; Medication is absorbed into the subcutaneous tissue; then absorbed into systemic circulation via capillariesthen absorbed into systemic circulation via capillaries
May take 18-24 hours before effect of medication May take 18-24 hours before effect of medication therefore therefore not idea for acute pain managementnot idea for acute pain management
Continue previous medicine for 18-24hr after placing Continue previous medicine for 18-24hr after placing the patchthe patch
Use short-acting opioid for rescue dosingUse short-acting opioid for rescue dosing Adjust dose no sooner than every 6 daysAdjust dose no sooner than every 6 days Once removing patch the effect may persist for up to Once removing patch the effect may persist for up to
24 hours24 hours
GOOD RULE OF THUMB: 2 X DURAGESIC DOSE = 24 HOUR MORPHINE DOSE
Duragesic: Oral Morphine Duragesic: Oral Morphine Equianalgesic TableEquianalgesic Table
Morphine dose in24hr
Duragesic PatchStrenth
90mg (range 45-134mg) 25ug/hr
180 (range 135-224mg) 50ug/hr
270 (range 225-314mg) 75ug/hr
360 (range 315-404mg) 100ug/hr
For each additional 90mg(range 45-134mg)
Add 25ug/hr
Steps in Changing Steps in Changing OpioidsOpioids
Calculate 24 hour dose of current opioidsCalculate 24 hour dose of current opioids Use equianalgesic table - convert dose of Use equianalgesic table - convert dose of
current drugs to equivalent new drugcurrent drugs to equivalent new drug Adjust the dose of new drug to accommodate Adjust the dose of new drug to accommodate
patient variability and incomplete cross patient variability and incomplete cross tolerancetolerance
Determine dosing intervals according to Determine dosing intervals according to duration of action of new opioidduration of action of new opioid
Calculate rescue doseCalculate rescue dose
Example:Example: Mr. Kaye is receiving 8mg Dilaudid Mr. Kaye is receiving 8mg Dilaudid po q 3h, and his physician would like to po q 3h, and his physician would like to change the patient to a sustained release change the patient to a sustained release morphine product for patient convenience.morphine product for patient convenience.
Calculate the 24 hour dose of DilaudidCalculate the 24 hour dose of Dilaudid– 8mg x 8 = 64mg Dilaudid8mg x 8 = 64mg Dilaudid
Using the morphine:Dilaudid ratio figure the 24 Using the morphine:Dilaudid ratio figure the 24 hour equianalgesic dose morphinehour equianalgesic dose morphine– Morphine: Dilaudid (4:1)Morphine: Dilaudid (4:1)– Multiply 64 by 4 = 256mg morphine equivalentMultiply 64 by 4 = 256mg morphine equivalent
Divide the 24 hour dose by 12 for the long-acting Divide the 24 hour dose by 12 for the long-acting morphine dosemorphine dose– 256 divided by 2 = 128 or rounded up to MS 256 divided by 2 = 128 or rounded up to MS
Contin 130mg q 12hourContin 130mg q 12hour
On the same patient, figure what the On the same patient, figure what the rescue dose of short-acting rescue dose of short-acting morphine would be?morphine would be?
Figure the total 24 hour dose of routine Figure the total 24 hour dose of routine medication being givenmedication being given– 260mg morphine per day260mg morphine per day
10% of that can be given every 1-2 10% of that can be given every 1-2 hours as needed for breakthrough painhours as needed for breakthrough pain– 10% of 260 = 26mg10% of 260 = 26mg– can give morphine immediate release can give morphine immediate release
tablets (30mg) q 1-2 h or morphine liquid tablets (30mg) q 1-2 h or morphine liquid (20mg/ml) 1.25 ml q 1-2 hour(20mg/ml) 1.25 ml q 1-2 hour
On the same patient, if he were On the same patient, if he were to stop swallowing what could to stop swallowing what could be done?be done? Switch to IV therapySwitch to IV therapy
– Figure the total dose of morphine given (260mg)Figure the total dose of morphine given (260mg)– Use the equianalgesic chart to figure oral:parenteral Use the equianalgesic chart to figure oral:parenteral
ratio (3:1)ratio (3:1)– Divide 260mg by 3 = 87mg IV morphine/dayDivide 260mg by 3 = 87mg IV morphine/day– Decide the route (subcutaneous or IV) Decide the route (subcutaneous or IV) – Divide 87mg/24hour = 3.6mg/hourDivide 87mg/24hour = 3.6mg/hour– Have boluses of 25-50% total hourly dose available q Have boluses of 25-50% total hourly dose available q
15-30mins (1-2mg)15-30mins (1-2mg) Use MS Contin rectallyUse MS Contin rectally at the same dose and give the at the same dose and give the
rescue dose as a sublingual medicationrescue dose as a sublingual medication Use sublingual medication on a q 4 hour scheduleUse sublingual medication on a q 4 hour schedule
On the same patient, if Mr. Kaye On the same patient, if Mr. Kaye stopped swallowing tablets but had stopped swallowing tablets but had an extended prognosis?an extended prognosis?
Consider switching to Duragesic PatchConsider switching to Duragesic Patch– Total Morphine dose 260mgTotal Morphine dose 260mg– Duragesic patch dose (per table) is Duragesic patch dose (per table) is
75ug/h75ug/h– Via 2x rule: 260/2=130 or 125ug/h Via 2x rule: 260/2=130 or 125ug/h – Same breakthrough medication is Same breakthrough medication is
appropriateappropriate Stop the previous routine medication Stop the previous routine medication
18-24 hours 18-24 hours afterafter the patch is placed the patch is placed
Bone Pain from Bone Pain from MetastasisMetastasis
NSAIDNSAID SteroidsSteroids BisphosphonatesBisphosphonates RadiopharmaceuticalsRadiopharmaceuticals Radiation TherapyRadiation Therapy
Neuropathic painNeuropathic pain Definition: Arising directly from Definition: Arising directly from
central and peripheral damage by central and peripheral damage by injury, disease or medical injury, disease or medical treatment. A pathological pain that treatment. A pathological pain that serves no adaptive purpose. serves no adaptive purpose.
Frequently becomes chronic and Frequently becomes chronic and may escalate over timemay escalate over time
Challenging to diagnose and treatChallenging to diagnose and treat
NOCICEPTORS react to noxiousstimuli (heat, chemical, mechanical)
A-delta fibersC fibers
Nociceptors terminate in the DORSAL HORN and
synapse in the Rexed Laminae
SPINOTHALAMIC TRACTSsend transmission rostrally after
decussating in spinal cord
Nociceptive signals ascend in the ANTEROLATERAL
WHITE MATTER
Termination in THALAMUSwith afferent fibers
projecting rostrally to the somatosensory
CORTEX and LIMBICSYSTEM
Afferent PainPathways
Mechanism and Mediators Mechanism and Mediators of Painof Pain
Painful stimuli causes depolarization of A-DELTA (thinly Painful stimuli causes depolarization of A-DELTA (thinly myelinated) and C-FIBER (unmyelinated)myelinated) and C-FIBER (unmyelinated)
Inflammation from chemical messengers released from Inflammation from chemical messengers released from damaged tissue (AMP, Protein), mast cells damaged tissue (AMP, Protein), mast cells (Prostaglandin), macrophages (cytokines)(Prostaglandin), macrophages (cytokines)
This leads to This leads to lowering of activation threshold and ectopic lowering of activation threshold and ectopic dischargesdischarges = = Peripheral sensitizationPeripheral sensitization
Neuron itself releases substance P which turns on Neuron itself releases substance P which turns on messengers of immune cellsmessengers of immune cells
Positive feedback loopPositive feedback loop Increase input into Dorsal HornIncrease input into Dorsal Horn
Peripheral Peripheral SensitizationSensitization
Lowering of the nociceptor Lowering of the nociceptor depolarization threshold and depolarization threshold and increase in ectopic dischargesincrease in ectopic discharges
Due to altered expression and Due to altered expression and distribution of sodium channels at distribution of sodium channels at the level of injured nociceptor and the level of injured nociceptor and Dorsal Root GanglionDorsal Root Ganglion
Mechanisms of Pain Mechanisms of Pain in the Dorsal Hornin the Dorsal Horn
Depolarized Nociceptors release Glutamate at Depolarized Nociceptors release Glutamate at the terminal endthe terminal end
Glutamate normally binds to AMPA receptor Glutamate normally binds to AMPA receptor causing depolarization of DH cellscausing depolarization of DH cells
With peripheral sensitization and increase input, With peripheral sensitization and increase input, the NMDA receptor becomes exposed and the NMDA receptor becomes exposed and Glutamate binds NMDA and AMPA. (wind-up)Glutamate binds NMDA and AMPA. (wind-up)
This sensitizes central nervous system such that This sensitizes central nervous system such that subthreshold input depolarize neuronssubthreshold input depolarize neurons
Central Central SensitizationSensitization
Lowering of the threshold of spinal horn Lowering of the threshold of spinal horn neurons, with an increase magnitude and neurons, with an increase magnitude and duration of response to stimulationduration of response to stimulation
Expansion in size of receptive fieldExpansion in size of receptive field Release of tachykinins (substance P and Release of tachykinins (substance P and
neurokinin A)neurokinin A)– These bind to neurokinin receptor and increase These bind to neurokinin receptor and increase
intracellular calcium intracellular calcium – Increases NMDA receptor up regulationIncreases NMDA receptor up regulation– Increase in Nitrous oxide synthetaseIncrease in Nitrous oxide synthetase
ImportanceImportance of NMDA of NMDA ReceptorReceptor
The NMDA Receptor is involved in the The NMDA Receptor is involved in the propagation of neuropathic pain propagation of neuropathic pain
Tolerance is also related to this Tolerance is also related to this receptorreceptor
When the NMDA Receptor is activated, When the NMDA Receptor is activated, there is Central Sensitization there is Central Sensitization
The opioid receptor, mu receptor, is The opioid receptor, mu receptor, is less responsive to opioidsless responsive to opioids
NEUROPATHIC PAIN
Medical Management
Surgical ManagementDecompression
Nerve BlocksLocal Anesthetics
Membrane stabilizingAgents
Drugs that enhancedorsal horn inhibition
NMDA ReceptorAntagonist
STEROIDSANTIARRHYTHMICS
LidocaineMexilitine
ANTIEPILEPTICSCarbamazepineOxcarbazepine
PhenytoinValproate
KetamineDextromethoraphan
MethadoneAmantadine
GABA-BagonistsBaclofen
ANTIDEPRESSANTSAmitriptylineDesipramineImipramine
Nortriptyline
ANTIEPILEPTICSOxcarbazepine
ClonazepamGabapentin
Most commonly used Most commonly used adjunctive treatmentsadjunctive treatments
AmitryptillineAmitryptilline CarbamazepineCarbamazepine GabapentinGabapentin CorticosteroidsCorticosteroids
MethadoneMethadone A Mu agonist and noncompetitive A Mu agonist and noncompetitive
NMDA receptor antagonistNMDA receptor antagonist No neuroactive metabolitesNo neuroactive metabolites Elimination is independent of renal Elimination is independent of renal
functionfunction Less constipating Less constipating Good oral bioavailabilityGood oral bioavailability Extremely low costExtremely low cost
Conversion to Conversion to MethadoneMethadone
Daily oral morphine doseequivalents
Conversion ratio of oralmorphine to methadone
< 100mg 3:1 (ie. 3mg morphine:1mgmethadone)
101-300mg 5:1
301-600mg 10:1
601-800mg 12:1
801-1000mg 15:1
> 1000mg 20:1
Interesting Case: 65yr old Interesting Case: 65yr old Anesthesiologist with Diabetic Anesthesiologist with Diabetic
Peripheral neuropathyPeripheral neuropathy
Mr. C. has stocking-glove distribution Mr. C. has stocking-glove distribution neuropathy. He had excruciating pain neuropathy. He had excruciating pain (10/10) while on Norco (10/325mg) 6-8 (10/10) while on Norco (10/325mg) 6-8 per day.per day.
Neurontin was not well toleratedNeurontin was not well tolerated Elavil was contraindicated due to cardiac Elavil was contraindicated due to cardiac
history and conduction system disorderhistory and conduction system disorder Mr. C. was depressed and didn’t think life Mr. C. was depressed and didn’t think life
was worth living with this painwas worth living with this pain
Neuropathic pain due to Neuropathic pain due to DiabetesDiabetes
After discussion with patient and family, After discussion with patient and family, we initiated a course of Methadonewe initiated a course of Methadone
His current dose of Hydrocodone was His current dose of Hydrocodone was 60-80mg daily or the equivalent of 60-60-80mg daily or the equivalent of 60-80mg morphine80mg morphine
My conversion with Methadone at low My conversion with Methadone at low dose morphine is 5:1dose morphine is 5:1
I started Mr. C on Methadone 5 mg q 8 I started Mr. C on Methadone 5 mg q 8 ATC with 2.5mg q 3 hours prnATC with 2.5mg q 3 hours prn
Methadone for Methadone for neuropathic painneuropathic pain
Patient tolerated Methadone wellPatient tolerated Methadone well Within 24 hours his 10/10 pain was Within 24 hours his 10/10 pain was
rated at 3/10rated at 3/10 Within 1 week, his pain was gone Within 1 week, his pain was gone
(0/10); (0/10); Precaution using MethadonePrecaution using Methadone: Slow : Slow
accumulation, varied half-life, needs to accumulation, varied half-life, needs to be adjusted upward slowly (about q 7 be adjusted upward slowly (about q 7 days)days)