pain management. overview barriers to pain management goals of pain management who ladder dosing and...
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Overview Barriers to pain
management Goals of pain
Management WHO ladder Dosing and
titration Routes of admin.
“Breakthrough pain”
Opiophobia Equianalgesic
ratios Opioid substitution Side effects Organ failure
Clinician-Related Barriers to Pain Assessment
Lack of formal training in pain management
Insufficient knowledge Lack of pain-assessment skills Rigidity or timidity in prescribing practices Fear of regulatory oversight
Portenoy RK Contemporary Diagnosis and Management of Pain in Oncologic and AIDS Patients 2001 Handbooks in Heathcare
Patient-Related Barriers to Pain Assessment
Reluctance to report pain (eg fear of distracting doctors from cure)
Reluctance to take opioid drugs Poor adherence
Portenoy RK 2001
System-Related Barriers to Pain Assessment
Low priority given to symptom control
(Availability of opioid analgesics) Inaccessibility/low profile of
specialised care Cost of outpatient pain medication
Portenoy RK 2001
Pain Assessment: Goals Assess the pain context Characterize the pain Identify pain syndrome Diagnose the cause Evaluate physical and
psychosocial co-morbidity Assess degree and nature of disability Develop a therapeutic strategy
Portenoy RK 2001
TOTALTOTALPAINPAIN
SOMATIC SOURCE
ANGERDEPRESSION
ANXIETY
Symptoms of debility
Side effects of therapy
Non-cancer pathology
Cancer
Bureaucratic bungling
Friends not visiting
Delays in diagnosis
Unavailable doctors
Irritability
Therapeutic failure
Fear of hospitalor nursing home
Worry about family
Fear of death
Spiritual (existential) unrest
Fear of pain
Family finances
Loss of choices
Uncertainty about future
Loss of social position
Loss of job prestigeand income
Loss of role in family
Chronic fatigueand insomnia
Sense of helplessness
Disfigurement
The Context
Pathophysiology
Nociceptive pain
Neuropathic pain
Commensurate with
identifiable tissue damage
May be abnormal, unfamiliar pain, probably caused by dysfunction in PNS or CNS
Nociceptive Pain Related to ongoing activation of primary
afferent neurons in response to noxious stimuli
Pain is consistent with the degree of tissue injury
Subtypes Somatic: well localized, described as sharp,
aching, throbbing Visceral: more diffuse, described as
gnawing or cramping Portenoy RK 2001
Neuropathic Pain Pain believed to be sustained by aberrant
somatosensory processing in the peripheral or central nervous system
Pain historyphenomenology
Temporal • Acute / recurrent / persistent• onset and duration• daily course
Intensity: ask the patient to rate• Average/worst / least / current
Topography: determine if pain is• Focal / multifocal / referred / deep
Quality: ask if it is• Numb/aching/stabbing/shooting/burning
Exacerbating relieving factors,
Pain history continued Medication
Side effects Organ function
Fears
Psychosocial context
World view/meaning
Narrative
Measurement
Investigationif it will aid management.
Only if potential benefit to patient May help identify management
option,XRAY (bone or joint pathology/ bowel obstruction) ,Bone Scan, CT, MRI
Investigation
Always in context benefit v burden
No mater how ‘simple’ the test, it may be abandoned as futile, if burden (as perceived by patient) outweighs potential benefit to patient.
Equally investigation may significantly guide appropriate treatment eg fractured neck of femur, best pain management is surgical management.
Approach to Pain Management
Raise the patients pain threshold Peripherally acting drugs eg paracetamol, Identify and engage a patient’s
psycho/social/spiritual resources Decrease the noxious stimulus
If appropriate disease modifying treatments eg surgery, chemotherapy, radiotherapy.
Treat other cause eg infection Use appropriately titrated strong opioid (centrally
acting). Diagnose, appropriately manage neuropathic pain,
consider specialist referral.
Approaching cancer pain relief European Journal of Pain, Volume 5, Supplement 1, December 2001, Pages 5-14 J. Norelle Lickis
Approach to Pain Management
Address psychosocial issues Anxiety Depression Spiritual distress Family conflict Financial issues
Principles of analgesic use
Three classes1. Nonopioid (paracetamol and
NSAIDs), 2. Opioid (weak and strong) and 3. Adjuvant (e.g.corticosteroids,
antidepressants, anticonvulsants, muscle relaxants).
WHO Method for Relief of Cancer Pain: 'By the mouth’
i.e. oral 'By the clock’ i.e. regular 'By the ladder'
(next slide)
Individualise treatment
Pay attention to detail
WHO ladder
Non opioids +/- adjuvant
Step 1
Step 2
Step 3
Weak opioid
+ non opioid
+/- adjuvant
Strong opioid
+ non opioid
+/- adjuvant
World Health Organization (1986) Cancer Pain Relief. World Health Organization, Geneva.
'Broad-spectrum analgesia'
The concept behind the analgesic ladder is
drugs from each of the three classes of analgesic are used appropriately either singly or in combination, to maximise their impact.
Step 1. Non-opioid
Use regular non-opioid as basis for analgesic regimen (WHO step 1).
Continue regular non-opioid and add in other agents (WHO steps 2 and 3) regular and prn.
Paracetamol improves pain and well being in people already receiving a strong opioid regimen. Vardy J et al 2004 J Clin Oncol 22:3389-3394
Hepatic toxicity is rare in doses less than 8g/d even in patients with chronic liver disease. Benson GD: Evaluation of the safety of acetaminophen in chronic liver disease. Clin Pharmacol Ther 33:95-101, 1983
WHO Step 2. Opioid analgesia
Opioid therapy is first line approach for moderate or severe cancer pain
Opioid therapy can relieve > 75% of cancer related pain
WHO Cancer Pain Relief 2nd ed a Guide to Opioid Availability. Geneva WHO 1996.
Opioid pharmacology
Opioids mimic actions of endogenous opioid compounds (endorphins)
Mu, kappa, delta Multiple subtypes Spinal cord, brain stem and peripheral
tissue
Portenoy RK 2001.
Dosing
Take into account• Is patient ‘naïve’ to opioids• pain aetiology• current 24hr dose• Absorption (decreased in constipated pt)• organ function• age• Co-morbidity• side effect v benefit
Titration
Titrate with immediate release medication Ensure regular dose plus appropriate
breakthrough available Note equianalgesic ratios Once stable convert to:
• Slow release• Trans-dermal if indicated
Routes of administration Oral where possible Slow release once requirement stable Subcutaneous if parenteral indicated (poor
swallowing, vomiting or constipation which may decrease absorption)
No indication for intramuscular Intravenous occasionally e.g PCA (patient
controlled analgesia) Consider trans-mucosal (expensive) Transdermal (only once stable)
Breakthrough pain
A transient, symptomatic exacerbation of pain
Exacerbations Pain that can occur as a
symptomatic overlay to baseline persistent pain.
Also described as "episodic," "incidental," and "transient" pain.
Breakthrough pain a transient exacerbation of pain
Superimposes otherwise stable baseline pain.
Describes worsening pain intensity as well as the transient nature of BTP symptoms.
Breakthrough pain a transient exacerbation of pain
For this definition to apply, baseline persistent pain should be stable.
Unstable baseline pain suggests the possibility that the baseline pain may not be accurately assessed or managed.
Widely changing baseline levels of pain may indicate:
• unrecognized breakthrough phenomena or • Inadequately treatment of persistent pain
• analgesics lacking enough potency or • duration of effect (dose).
Breakthrough pain Subtypes of Breakthrough Pain (BTP)
Bennet D, Burton AW, Fishman S, et al. Consensus panel recommendations for the assessment and management of breakthrough pain: part 1. Treatment. Pharmacol Ther. 2005;30:296-301.
http://www.medscape.com/viewprogram/4270
Anticipatory doses Given prophylactively prior to
expected painful activity eg mobilising, dressing changes or other procedure.
Timed to coincide with the peak plasma concentration of particular analgesic eg 20mins Endone or oral morphine.
Dose adjustment
If the patient's pain improves, e.g. as a result of radiotherapy or a nerve block, dose reduction may be required to prevent side effects e.g. sedation.
• Hanks GW, Twycross RG, Lloyd JW. Unexpected complication of successful nerve block. Morphine induced respiration precipitated by removal of severe pain. Anaesthesia 1981; 36;37-39
Opiophobia - myths to be dispelled
Nearly all patients and many clinicians fear that morphine Is addictive even if used correctly for pain Should be reserved for patients who are
dying because • It may hasten death• Tolerance will limit duration of effective analgesia
Side effects are worse than pain
There is evidence to support the consensus that none of these are true
Tolerance to strong opioids
Patients fear tolerance (“I don’t want morphine until I really need it!”)
Disease progression is the major factor in opioid dose increases in cancer pain management.
Increase in pain will usually respond to up titration of opioid dose.
Patients who have pain and receive opioid analgesia. live longer than those who don’t receive opioids
• Collins E, Poulain P Gauvin-Piquard A et al Pain 1981; Suppl 1:S39.• A Thorns; N Sykes The Lancet; Jul 29, 2000; 356, 9227; pg. 398
Tolerance to strong opioids. In practice rarely a problem. Patients fear of developing psychological
dependence (addiction) is unfounded Should not limit the use of strong opioids for
cancer pain. Caution in this respect should be reserved for
patients with a present or past history of substance abuse.
Patients with significant cancer pain and a history of drug use often require a steep titration phase for opioid therapy. Seek specialist help.
Twycross R, Wilcox A et al Palliative Care Formulary 2002
Opioid Substitution
In patients who have intolerable adverse effects with morphine, it may be necessary to substitute an alternative strong opioid.
If increase in dose is met by unacceptable side effects with no improvement in pain.De Stouts, Bruera E, Suarez-Almazor AAM: Opioid rotation for toxicity reduction in
terminal cancer ptients. J Pain and Symptom Manage 1995; 10:378-384
Respiratory Depression
Pain is a physiological antagonist to the central depressant effects of morphine
Chronic dosing with appropriately titrated strong opioids do not cause clinically important respiratory depression in cancer patients in pain when used correctly.
Caution in sleep apnoea (CAL generally safe if correct titration)
Twycross R, Wilcox A et al Palliative Care Formulary 2002
Respiratory Depression
Less likely when patients: are not opioid naive take medication by mouth (slower
absorption, lower peak concentration) titration of the dose upwards occurs
step by step (less likelihood of an excessive dose being given).
Opioid side effects Constipation
Education and prophylaxis for almost all patients e.g. Movicol, Coloxyl with Senna
Avoid bulking agents Nausea
Consider prophylaxis if pt nervous or history of nausea
Neurotoxicity • Mild: subjective experience of altered mental state, • moderate: drowsiness, • severe: delirium, myoclonus, seizures (inappropriate
titration or organ failure)
Organ Failure Renal failure significant in terms of
increased elimination half life and accumulation of toxic metabolites Dose adjustment Dosing interval adjustment
Choice of analgesic - seek specialist advice
Organ Failure Liver failure in practice largely not
significant
Hepatic encephalopathy, as with any cause of delirium may increase neurotoxic side effects.
Summary 1
1. 75% of cancer pain can be controlled with simple measures eg appropriately titrated morphine and regular paracetamol
2. Don’t forget constipation prophylaxis3. Dose adjust in renal failure4. Have a high index of suspicion for co-
morbid delirium (eg infection, hypercalcaemia) if confusion develops
5. Avoid the traps of opiophobia
Summary 2
1. Reduce the noxious stimulus• Diagnose the cause• Treat where possible and appropriate• Use regular non-opioid eg paracetamol
2. Raise the patient’s pain threshold• Address bio/psycho/social/spiritual patient needs and resources
3. Opioids: first line treatment for moderate to severe Ca pain.
• Use appropriate regular + prn / route / choice of drug / care in renal failure.• Address myths and opio-phobia
4. Know how to diagnose and manage neuropathic pain
• Patient descriptors numb/shooting/burning/toothache like
5. Consult specialist as required6. Don’t neglect the patients psychosocial issuesVardy J et al 2004 J Clin Oncol 22:3389-3394
References
1. Hanks GW, et al. Morphine and alternative opioids in cancer pain: the EAPC recommendations BRITISH JOURNAL OF CANCER 84 (5): 587-593 MAR 2 2001
2. Lickiss JN. Approaching cancer pain relief. Eur J Pain 2001; 5 (Suppl A): 514
3. Glare, P et al Ongoing controversies in the pharmacological management of cancer pain. INTERNAL MEDICINE JOURNAL 34 (1-2), 45-49.
4. Thorns A, Sykes N. Opioid use in the last week of life and implications for end-of-life decision-making. LANCET. 2000 Jul 29;356(9227):398-9.
5. Indelicato RA, Portenoy RK, : Opioid rotation in the management of refractory cancer pain. JOURNAL OF CLINICAL ONCOLOGY 20 (1): 348-352 JAN 1 2002