Transcript Harlos – U of Manitoba

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. Pause here - discuss with patient/family the goals of care,
hopes, expectations, anticipated course of illness. This will
influence consideration of investigations and interventions
3. Investigations – X-Ray, CT, MRI, etc - if they will affect
approach to care
4. Treatments – pharmacological and non-pharmacological;
interventional analgesia (e.g.. Spinal)
5. Ongoing reassessment and review of options, goals,
expectations, etc.
TYPES OF PAIN
NOCICEPTIVE
NEUROPATHIC
Visceral
Somatic
• bones, joints
• connective tissues
• muscles
• 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
EXAMPLES
• Diabetic neuropathy
• Post-herpetic
neuropathy
• Hypersthesia
Paroxysmal,
Neuralgic
• Stabbing
• trigeminal neuralgia
• Shock-like, electric
• may be a component
of any neuropathic
pain
• Shooting
• Lancinating
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
3
By the
Strong opioid
+/- adjuvant
2
Clock
1
Non-opioid
+/- adjuvant
Weak 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
Hydromorphone
5 10 15 20 25 30 40 50 60
1
2
3
4
5
6
8 10 12
http://palliative.info
http://palliative.info
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 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 – uncommon when titrated in
response to symptom
 Drug interactions
 Neurotoxicity (OIN): delirium, myoclonus  seizures
Spectrum of Opioid-Induced Neurotoxicity
Opioid
tolerance
Mild myoclonus
(eg. with sleeping)
Delirium
Opioids
Increased
Severe myoclonus
Seizures,
Death
Hyperalgesia
Agitation
Misinterpreted
as Pain
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 – 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
Having a steady level of enough opioid to treat
the peaks of incident pain...
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
mg/ml)
# Micrograms Sublingually
1
Fentanyl
50
2
Sufentanil
25
3
Sufentanil
50
4
Sufentanil
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