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

1.

Thorough assessment by skilled and knowledgeable clinician – History – Physical Examination 2.

3.

4.

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 -

approach to care if they will affect

Treatments – pharmacological and non-pharmacological; interventional analgesia (e.g.. Spinal) 5.

Ongoing reassessment and review expectations, etc.

of options, goals,

TYPES OF PAIN

NOCICEPTIVE NEUROPATHIC

• • •

Somatic

bones, joints connective tissues muscles

Visceral

•

Organs – heart, liver, pancreas, gut, etc.

Deafferentation Sympathetic Maintained Peripheral

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

FEATURES OF NEUROPATHIC PAIN

COMPONENT

Steady, Dysesthetic

DESCRIPTORS • Burning, Tingling • Constant, Aching • • • Squeezing, Itching

Allodynia Hypersthesia Paroxysmal, Neuralgic

EXAMPLES • Diabetic neuropathy • Post-herpetic neuropathy • Stabbing • Shock-like, electric • Shooting • Lancinating • trigeminal neuralgia • may be a component of any neuropathic pain

Pain Assessment

“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?

Example Of A Numbered Scale

• • • • • •

Medication(s) Taken

Dose Route Frequency Duration Efficacy Adverse effects

Physical Exam In Pain Assessment

Inspection / 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 Assessment

Palpation  Localized tenderness to pressure or percussion  Fullness / mass  Induration / warmth

Physical Exam In Pain Assessment

Neurological 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 Assessment

Other 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.

Pain Treatment

Non-Pharmacological Pain Management

 Acupuncture  Cognitive/behavioral therapy  Meditation/relaxation  Guided imagery  TENS  Therapeutic massage  Others…

W.H.O. ANALGESIC LADDER

By the Clock

1

Non-opioid +/- adjuvant

2

Weak opioid +/- adjuvant

3

Strong opioid +/- adjuvant

STRONG OPIOIDS

• most commonly use: – morphine – Hydromorphone (Dilaudid ®) – transdermal fentanyl (Duragesic®) – oxycodone – Methadone • DO NOT use meperidine (Demerol  ) 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) Morphine 5 10 15 20 25 30 40 50 60 Hydromorphone 1 2 3 4 5 6 8 10 12

http://palliative.info

http://palliative.info

TOLERANCE PHYSICAL DEPENDENCE PSYCHOLOGICAL DEPENDENCE / ADDICTION

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 a withdrawal

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

reduce by ½

SQ / IV / IM routes

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 response to symptom – uncommon when titrated in Drug interactions Neurotoxicity (OIN): delirium, myoclonus  seizures

Spectrum of Opioid-Induced Neurotoxicity Opioid tolerance Mild myoclonus (eg. with sleeping) Severe myoclonus Seizures, Death Delirium Opioids Increased Agitation Misinterpreted as Pain Hyperalgesia Opioids Increased Misinterpreted as Disease-Related Pain

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

} 

tumor mass effects



spontaneous nerve depolarization

CORTICOSTEROIDS: ADVERSE EFFECTS

IMMEDIATE  Psychiatric  Hyperglycemia  risk of GI bleed  gastritis  aggravation of existing lesion (ulcer, tumor)  Immunosuppression LONG-TERM     Proximal myopathy often < 15 days Cushing’s syndrome Osteoporosis Aseptic / avascular necrosis of bone

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 – TCAs (for dysesthetic pain, esp. if depression) NMDA receptor antagonists: ketamine, methadone Anesthetics

gabapentin, topiramate

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

Having a steady level of enough opioid to treat the peaks of incident pain...

...would result in excessive dosing for the periods between incidents Incident Incident Time Incident

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)

Step # Medication (50 m g/ml) 1 2 3 4 Fentanyl Sufentanil Sufentanil Sufentanil # Micrograms Sublingually 50 25 50 100

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