Pain Management In Palliative Care Mike Harlos MD, CCFP, FCFP Professor and Section Head, Palliative Medicine, University of Manitoba Medical Director, WRHA Palliative Care Medical Director, Pediatric Symptom Management Service
Pain An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. International Association for the Study of Pain
Clinical Terms For The Sensory Disturbances Associated With Pain • Dysesthesia – An unpleasant abnormal sensation, whether spontaneous or evoked. • Allodynia – Pain due to a stimulus which does not normally provoke pain, such as pain caused by light touch to the skin • Hyperalgesia – An increased response to a stimulus which is normally painful • Hyperesthesia - Increased sensitivity to stimulation, excluding the special senses. Hyperesthesia includes both allodynia and hyperalgesia, but the more specific terms should be used wherever they are applicable.
Approach To Pain Control in Palliative Care • Thorough assessment by skilled and knowledgeable clinician • History • Physical Examination • Pause here - discuss with patient/family the goals of care, hopes, expectations, anticipated course of illness. This will influence consideration of investigations and interventions • Investigations – X-Ray, CT, MRI, etc - if they will affect approach to care • Treatments – pharmacological and non-pharmacological; interventional analgesia (e.g.. Spinal) • Ongoing reassessment and review of options, goals, expectations, etc.
Visceral Somatic • bones, joints • connective tissues • muscles • Organs – heart, liver, pancreas, gut, etc. Deafferentation Sympathetic Maintained Peripheral TYPES OF PAIN NEUROPATHIC NOCICEPTIVE
Somatic Pain • Aching, often constant • May be dull or sharp • Often worse with movement • Well localized • Eg/ • Bone & soft tissue • chest wall
Visceral Pain • Constant or crampy • Aching • Poorly localized • Referred • Eg/ • CA pancreas • Liver capsule distension • Bowel obstruction
“Describing pain only in terms of its intensity is like describing music only in terms of its loudness” von Baeyer CL; Pain Research and Management 11(3) 2006; p.157-162
PAIN HISTORY • Description: severity, quality, location, temporal features, frequency, aggravating & alleviating factors • Previous history • Context: social, cultural, emotional, spiritual factors • Meaning • Interventions: what has been tried?
Medication(s) Taken • Dose • Route • Frequency • Duration • Efficacy • Adverse effects
Physical Exam In Pain AssessmentInspection / Observation “You can observe a lot just by watching” Yogi Berra • Overall impression… the “gestalt”? • Facial expression: Grimacing; furrowed brow; appears anxious; flat affect • Body position and spontaneous movement: there may be positioning to protect painful areas, limited movement due to pain • Diaphoresis – can be caused by pain • Areas of redness, swelling • Atrophied muscles • Gait • Myoclonus – possibly indicating opioid-induced neurotoxicity
Physical Exam In Pain AssessmentPalpation • Localized tenderness to pressure or percussion • Fullness / mass • Induration / warmth
Physical Exam In Pain AssessmentNeurological Examination • Important in evaluating pain, due to the possibility of spinal cord compression, and nerve root or peripheral nerve lesions • Sensory examination • Areas of numbness / decreased sensation • Areas of increased sensitivity, such as allodynia or hyperalgesia • Motor (strength) exam - caution if bony metastases (may fracture) • Deep tendon reflexes – intensity, symmetry • Hyperreflexia and clonus: possible upper motor neuron lesion, such as spinal cord compression or cerebral metastases. • Hyoporeflexia - possible lower motor neuron impairment, including lesions of the cauda equina of the spinal cord or leptomeningeal metastases. • Sacral reflexes – diminished rectal tone and absent anal reflexes may indicate cauda equina involvement of by tumour
Physical Exam In Pain AssessmentOther Exam Considerations Further areas of focus of the physical examination are determined by the clinical presentation. Eg: evaluation of pleuritic chest pain would involve a detailed respiratory and chest wall examination.
Non-Pharmacological Pain Management • Acupuncture • Cognitive/behavioral therapy • Meditation/relaxation • Guided imagery • TENS • Therapeutic massage • Others…
3 By the 2 Clock 1 W.H.O. ANALGESIC LADDER Strong opioid +/- adjuvant Weak opioid +/- adjuvant Pain persists or increases Non-opioid +/- adjuvant
STRONG OPIOIDS • most commonly use: • morphine • Hydromorphone (Dilaudid ®) • transdermal fentanyl (Duragesic®) • oxycodone • Methadone • DO NOT use meperidine (Demerolâ) long-term • active metabolite normeperidine®seizures
OPIOIDS and INCOMPLETE CROSS-TOLERANCE • conversion tables assume that tolerance to a specific opioid is fully “crossed over” to other opioids. • cross-tolerance unpredictable, especially in: • high doses • long-term use • divide calculated dose in ½ and titrate
TITRATING OPIOIDS • dose increase depends on the situation • dose by 25 - 100% EXAMPLE: (doses in mg q4h)
TOLERANCE PSYCHOLOGICAL DEPENDENCE / ADDICTION PHYSICAL DEPENDENCE
TOLERANCE A normal physiological phenomenon in which increasing doses are required to produce the same effect Inturrisi C, Hanks G. Oxford Textbook of Palliative Medicine 1993: Chapter 4.2.3
PHYSICAL DEPENDENCE A normal physiological phenomenon in which awithdrawal syndrome occurs when an opioid is abruptly discontinued or an opioid antagonist is administered Inturrisi C, Hanks G. Oxford Textbook of Palliative Medicine 1993: Chapter 4.2.3
PSYCHOLOGICAL DEPENDENCE and ADDICTION A pattern of drug use characterized by a continued craving for an opioid which is manifest as compulsive drug-seeking behaviour leading to an overwhelming involvement in the use and procurement of the drug Inturrisi C, Hanks G. Oxford Textbook of Palliative Medicine 1993: Chapter 4.2.3
Changing Route Of Administration In Chronic Opioid Dosing • po / sublingual / rectal routes • SQ / IV / IM routes reduce by ½
Using Opioids for Breakthrough Pain • Patient must feel in control, empowered • Use aggressive dose and interval • Patient Taking Short-Acting Opioids: • 50 - 100% of the q4h dose, given q1h prn • Patient Taking Long-Acting Opioids: • 10 - 20% of total daily dose given, q1h prn • with short-acting opioid preparation
Opioid Side Effects • Constipation – need proactive laxative use • Nausea/vomiting – consider treating with dopamine antagonists and/or prokinetics (metoclopramide, domperidone, prochlorperazine [Stemetil], haloperidol) • Urinary retention • Itch/rash – worse in children; may need low-dose naloxone infusion. May try antihistamines, however not great success • Dry mouth • Respiratory depression – uncommon when titrated in response to symptom • Drug interactions • Neurotoxicity (OIN):delirium, myoclonus ® seizures
Delirium Hyperalgesia OpioidsIncreased Agitation OpioidsIncreased Misinterpretedas Disease-Related Pain Misinterpretedas Pain Spectrum of Opioid-Induced Neurotoxicity Opioidtolerance Mild myoclonus(eg. with sleeping) Seizures,Death Severe myoclonus
OIN: Treatment • Switch opioid (rotation) or reduce opioid dose; usually much lower than expected doses of alternate opioid required… often use prn initially • Hydration • Benzodiazepines for neuromuscular excitation
Adjuvant Analgesics • first developed for non-analgesic indications • subsequently found to have analgesic activity in specific pain scenarios • Common uses: • pain poorly-responsive to opioids (eg. neuropathic pain), or • with intentions of lowering the total opioid dose and thereby mitigate opioid side effects.
Adjuvants Used In Palliative Care • General / Non-specific • corticosteroids • cannabinoids (not yet commonly used for pain) • Neuropathic Pain • gabapentin • antidepressants • ketamine • topiramate • clonidine • Bone Pain • bisphosphonates • (calcitonin)
CORTICOSTEROIDS AS ADJUVANTS • ¯ inflammation • ¯ edema • ¯ spontaneous nerve depolarization } ¯ tumor mass effects
DEXAMETHASONE • minimal mineralcorticoid effects • po/iv/sq/?sublingual routes • perhaps can be given once/day; often given more frequently • If an acute course is discontinued within 2 wks, adrenal suppression not likely
Treatment of Neuropathic Pain Pharmacologic treatment • Opioids • Steroids • Anticonvulsants – gabapentin, topiramate • TCAs (for dysesthetic pain, esp. if depression) • NMDA receptor antagonists: ketamine, methadone • Anesthetics Radiation therapy Interventional treatment • Spinal analgesia • Nerve blocks
Gabapentin • Common Starting Regimen • 300 mg hs Day 1, 300 mg bid Day2, 300 mg tid Day 3, then gradually titrate to effect up to 1200 mg tid • Frail patients • 100 mg hs Day 1, 100 mg bid Day 2, 100 mg tid Day 3, then gradually titrate to effect
Incident Pain Pain occurring as a direct and immediate consequence of a movement or activity
Circumstances In Which Incident Pain Often Occurs • Bone metastases • Neuropathic pain • Intra-abd. disease aggravated by respiration • “incident” = breathing • ruptured viscus, peritonitis, liver hemorrhage • Skin ulcer: dressing change, debridement • Disimpaction • Catheterization
Incident Incident Incident Having a steady level of enough opioid to treat the peaks of incident pain... ...would result in excessive dosing for the periods between incidents Pain Time
Fentanyl and Sufentanil • synthetic µ agonist opioids • highly lipid soluble • transmucosal absorption; effect in approx 10 min • rapid redistribution, including in / out of CSF; lasts approx 1 hr. • fentanyl » 100x stronger than morphine • sufentanil » 1000x stronger than morphine 10 mg morphine » 10 µg sufentanil » 100 µg fentanyl
INCIDENT PAIN PROTOCOL (see also http://palliative.info)
INCIDENT PAIN PROTOCOL ctd... • fentanyl or sufentanil is administered SL 10 min. prior to anticipated activity • repeat q 10min x 2 additional doses if needed • increase to next step if 3 total doses not effective • physician order required to increase to next step if within an hour of last dose • the Incident Pain Protocol may be used up to q 1h prn