Download Opioids in Persistent Pain

An interactive work shop with CGPI – Winter ASM and
FPMCAI (Drs Power/Keaveny)
British Pain Society Guidelines
Key Topics for discussion
 Opioid Pharmacology
 Why Prescribe?
 Adverse effects
 Practical Prescribing
 Opioids and problem drug use
Clinical Opioid Pharmacology
 Agonists at endogenous receptors
 Widespread receptor network in CNS/Some
differential activity ? Clinical significance
 Variable clinical response - switching opioids is a valid
option
 Dose ratios vary - individual prescribing
 Strong / weak opioids (codeine/DFII8/Meptazinol) –
tradition!
 Controlled drugs
Why Prescribe?
 Useful analgesia in the short to medium term ( longer
term – jury is out)
 Efficacy in somatic, visceral, neuropathic pain
 Target 50% plus pain relief to facilitate rehabilitation
and restoration of function
 Improvements in related bio psychosocial domains
including sleep and mood sought but evidence base
only for sleep (as a consequence of pain reduction)
Why Prescribe?
 Opioids should not be used as hypnotics, sedatives,
antidepressants,
 Opioids should be part of a broader bio psychosocial
approach – exercise, relaxation, goal setting to achieve
return to function, pacing, education, cognitive
resilience
Adverse Effects / Tolerance
 Constipation (persists)
 Nausea
 Somnolence
 Itching (persists)
 Dizziness
 Vomiting
Adverse Effects
 Active Mx
 Respiratory Depression acute/chronic/ sleep apnoea/
respiratory problems/overdose/ sedatives
 Drug side-effect profiles similar but patient genetics
different (rotation options)
Opioid Toxicity/individual
variability / medical co morbidities
 Pinpoint pupils
 Sedation
 Slow respiration
 Myoclonic jerks
 Snoring when asleep
 Agitation/confusion
 Vivid dreams/ nightmares / hallucinations
 Severe: Hypotension/coma / convulsions
Opioid Withdrawal
 Sweating
 Mydriasis
 Yawning/piloerection
 Abdo cramps / v/d
 Musculoskeletal pain
 Increase in usual pain
 Anxiety/tremor
 Rhinorrhoea/Lacrimation
Long term effects of opioids
 Endocrine effects of Opioids – HPA axis and HP
gonadal axis – Hypogonadism and hypoadrenalism in
both sexes
 Amenorrhoea, reduced libido,infertility, and
depression in women, erectile dysfunction
 Immunology – immunosuppresion ( not
buprenorphine)
Opioid induced Hyperalgesia
 Abnormal pain sensitivity – increased pain
 Diffuse quality
 Opioid reduction /rotation
Practical Prescribing
 Psychological evaluation – depression, substance
misuse, PTSD – tx first or in tandem
 Competent patient/carer ( side effect recognition and
mx)
 Elderly dose reductions and frequent evaluations
 Frontline TCADS/anticonvulsants – trial first
 Explain risk / benefits and document
 Set Goals / re evaluate and document
Practical Prescribing
 Regular by the clock, by the mouth/skin and not by
the pain
 Some exceptions – intermittent and short lived,
diurnal variation
 Injections for persistent pain almost never
 No Pethidine
 Serotonin syndrome ( caution re tramadol with
TCAD’s/SSRI’s)
Practical Prescribing
 Low dose / titrate up to a reasonable level ( 3
adjustments)
 120 to 180 mgs max in 24 hours
 Opioid contract – agreed pain goals, obligations,
functional goals, mx of side effects etc
 If trial fails terminate / wean off opioids and document
 Review intervals
Opioids and Problem Drug use
 Substance misuse – discuss/document
 Drug diversion / drug testing
 Tolerance /dependence /addiction/pseudo addiction
Addiction
a primary chronic neurobiological
disease – genetic, psychosocial and environmental factors – with some of the
following behaviours
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Impaired control over drug use
Compulsive use
Continued use despite harm
Craving
Pseudo addiction – behaviours related to inadequate
pain relief such as hoarding, extra supplies early
prescriptions – settles on correct dose
Risk Factors
 Current or past history of substance misuse
 Family member with history of substance misuse
 Poor social support
 Co morbid psychiatric disorders
Physical dependence /Tolerance
(APS)
 Physical dependence - is a state of adaption that is
manifested by a drug class specific withdrawal syndrome
that can be produced by abrupt cessation, rapid dose
reduction decreasing blood level of the drug or
administration of an antagonist.
 Tolerance - is a state of adaptation in which exposure to a
drug induces changes that result in a diminution of one or
more of the drugs effects over time
BEHAVIOURS WHICH INDICATE PROBLEM DRUG
USE
 Earlier prescription seeking
 Claims of lost medication
 Intoxication
 Frequent missed appointments
 Use of other scheduled drugs
Increased need for medication
 Disease progression
 New pain problem
 Opioid tolerance
 Opiod induced hyperalgesia
 Problem drug use
A pain medicine algorithm
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Precision diagnosis (red flags)
Bio psychosocial assessment ( yellow flags)
Role of intervention
Medication – paracetemol/topical nsaids, lignocaine,
capsaicin, neuropathic pain meds, weaker opioids
Discuss opioids – benefits, problems, document
Trial 4 to 12 weeks / set goals / contract
Assess – semi formal trial – if no benefit wean off
If beneficial proceed to stable dosing pattern/ be
cautious in escalating dosage pressures