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Pain Management in the Elderly
Rog Kyle
10/7/11
Aging Q3 ACOVE #10
Background
• Chronic pain (cancer and non-cancer)
problematic in 25-50% of elders in the
community
• Osteoarthritis (and other musculoskeletal) is
most common cause
• Low back pain (LBP) most prevalent condition
– 10 million Americans disabled
• Others
– Postherpetic neuralgia (PHN)
– Painful diabetic neuropathy
– Post stroke pain
• Cancer pain
– 80% of elderly with cancer report pain
– Probably under detected and under treated
– Deficiencies
• Under documented
• Under treated – opioids and non-opioids
• Reporting by patients
– Most feared complication of illness
– Pain is the second leading complaint in physicians’
offices
– Effects on mood, functional status, and quality of
life
– Associated with increased health resources use
• Barriers to reporting
– Cognitively impaired
– More tests
– Fear of medications
– Fear of the cause for the pain
– Complaining may effect quality of care
– Believe nothing can or will be done
• Hospitalized patients
– No randomized trials
– Prospective studies on cancer patients
• Underestimate pain
• Probably do not assess frequently enough
Challenges in the elderly
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Comparatively little data
Cognitive impairment and compliance
Underreported by patients
Drug-drug interaction and polypharmacy a
serious concern
• Reduced hepatic function, reduced renal
function
Mechanisms for pain
• Nociceptive
– Nociceptors = pain fiber sensitive to noxious
stimuli
• Somatic – injury to tissues, well localized
• Visceral – injury to organs (stretch receptors),
poorly localized
• Neuropathic
– Abnormal neural activity secondary to disease, injury, or
dysfunction (allodynia).
– Persists without ongoing injury (trigeminal neuralgia, DM
neuropathy)
– Types:
• Sympathetic – from peripheral nerve injury with
autonomic changes
– “New” term – Complex Regional Pain Syndrome
(CRPS)
• Type I = RSD
• Type II = causalgia
• Peripheral autonomic pain –
– Same but without autonomic change (PHN)
• Central Pain (spinal cord injury)
Pain pathways
• Nociceptive fibers – afferent fibers to dorsal horn
– Two types
• A-delta – sharp pain (fast)
• C polymodal – dull pain (slow)
• Pathways
• Nociceptive fibers – afferent fibers to dorsal horn
– Two types
• A-delta – sharp pain (fast)
• C polymodal – dull pain (slow)
• Pathways
• Central processing
– Interneurons between spinal
cord/thalamus/cortex modulate pain and may be
either excitatory of inhibitory
– endogenous systems also control pain perception
– opioid, noradrenergic (fight or flight), and
serotonergic
Mechanisms for chronic pain
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Peripheral sensitization
Central sensitization
Disinhibition
Desensitization
Ectopic excitability
Structural reorganization
Phenotypic switch of neurons
Primary sensory degeneration
Sensitization
• Main cause for hypersensitivity to pain after an injury
(nociceptive sensitizer)
• Each has it’s own proposed mechanism at the cellular
level
– Peripheral – injury/inflammation releases
cytokines, chemokines, bradykinin, histamine,
prostaglandins
– Central – amplifies info from nociceptors – NMDA
receptor upregulated (controls pain – ketamine),
GABA inhibition - disinhibition - “inhibits
inhibition”
Treatment – non drug strategies
• Exercise
– PT, OT, stretching, strengthening
– general conditioning
• Physical methods
– ice, heat, massage
• Cognitive-behavioral therapy
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Chiropracty
Acupuncture
TENS
Alternative therapies
– relaxation, imagery
– herbals
WHO Ladder (adapted for elderly)
– Level 3 (severe pain): Strong
• opioids—morphine, hydromorphone,
• fentanyl, oxycodone ±adjuvants
– Level 2 (moderate to severe pain):
• Acetaminophen plus opioid (hydrocodone,
• oxycodone, codeine); tramadol ±adjuvants,
• Propoxyphene (X)
– Level 1 (mild to moderate pain):
• Acetaminophen, aspirin (X), nonspecific NSAIDs (X),
• COX-2–specific NSAIDs±adjuvants
Figure 1. WHO ladder (adapted for the elderly).
Note: Therapies marked with an “X” are not appropriate for use in the elderly.
Non-opioid options
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Acetaminophen
Alpha-adrenergic agents
Anticonvulsants
Antidepressants
Muscle relaxants
Neuroleptic agents
NMDA-receptor antagonists
NSAIDs
Oral local anesthetics
Topical analgesics
Acetaminophen
• First line
• 4000mg max
– 2000mg recommended with etoh use, liver
disease, elderly
• Watch for other OTC’s containing
acetaminophen
Alpha-adrenergics
• Epidural clonidine for neuropathic pain (FDA)
• Tizanidine outside US
Anticonvulsants
• Neuropathic pain
• Second gen may have fewer side effects
(gabapentin, topiramate)
• Many approved for HA/pain
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Carbamazepine (trigeminal neuralgia)
Divalproex (migraine)
Gabapentin (PHN)
Pregabalin (PHN, diabetic neuropathy)
Topiramate (migraine)
Duloxetine (diabetic neuropathy, fibromyalgia, DJD)
• Off label
– Lamotrigine for HIV neuropathy (and others)
– PDN
• Carbamazepine, phenytoin, gabapentin
– Chronic musculoskeletal pain
Antidepressants
• Analgesia independent of antidepressant effects
• Tricyclics (amitriptyline) for neuropathic pain
– Nortriptyline has safer side effect profile in > 60
– Amitriptyline relatively contraindicated in elderly
(cardiac, anticholinergic)
• SNRI’s
– Duloxetine, venlafaxine
• Others
– Bupropion, venlafaxine, duloxetine (neuropathic)
• SSRI’s/SNRI’s not shown to have efficacy
comparable to tricyclics
TRICYCLIC
SSRI
Amitriptyline
Desipramine
Doxepin
Imipramine
Nortriptyline
Fluoxetine
Paroxetine
Sertraline
Fluvoxamine
Citalopram
*FDA approved for pain
OTHER
Venlafaxine
Duloxetine*
Trazodone
Bupropion
Muscle relaxants
• Cyclobenzaprine
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Similar to tricyclic's
Acute LBP (2 trials)
Anticholinergic side effects, cardiac arrhythmia
Avoid in elderly
• Carisoprodol (meprobamate precursor)
– Acute LBP
– Dependency (physical, psychological), drowsiness
• Metaxalone (Skelaxine)
– Non-sedating, watch for liver tox
• Baclofen
– GABA agonist
Neuroleptics
• Fluphenaxine (Prolixin)
– Not recommended
NMDA receptor antagonists
• Scientific promise
– Dextromethorphan
– Ketamine
– Methadone
– Memantine
– Amitriptyline
NSAIDS
• 60 million Rx’s/yr (3.6 fold higher in elders)
• Clinical efficacy of equipotent doses is similar
• Individual responses highly variable – especially toxicity
– cox-1 vs. cox-2
– naprosyn may have greatest relative cardiovascular safety profile
– diclofenac - available as a topical patch for pain due to trauma and
as a gel for treatment of painful joints
– sulindac – increased hepatoxicity
– indomethacin - GI and central nervous system adverse effects may
be more frequent or severe than with other NSAIDs
– ketorolac - Risk of gastropathy is increased when use exceeds five
days
– piroxicam – high GI toxicity
– celecoxib – no antiplatelet function. Increased CV risk above
200mg/day
• Generally indicated in mild to moderate pain
• Mostly for pain of somatic origin although has
a CNS effect as well
• Each trial should last a couple weeks
• May have an opioid sparing effect as adjunct
• Protein bound – may interfere with other
protein bound drugs (dilantin. coumadin)
• Noted variability in the response to NSAIDS between
patients
– Does not appear related to serum concentrations
– Degree of Cox inhibition doesn’t correlate with effect
– Non-prostaglandin effects may predominate in some
patients
– Switching between classes of NSAIDS may be
beneficial
Topicals
• Lidoderm
– FDA approved for PHN (intact skin)
– Often used in musculoskeletal pain
• Diclofenac patch
– Topical treatment of acute (short-term) pain due
to minor strains, sprains, and contusions (bruises)
• Capsaicin
– Neurotransmitter depletion
– PHN, musculoskeletal
Tramadol
• Mu receptor and SNRI effects
• Effective in neuropathic pain, fibromyalgia, OA
• Similar side effects to opioids
– Seizures, suicide
Benzodiazepines
• Adjuvant only
• Anxiolytic
• Limitations
– Sedation
– Addictive potential
– Respiratory depression
– Avoid in elderly
• Clonazepam
– Effective in PHN and myoclonus
Opioids
• Role in treatment of pain is well established for
acute pain, malignant pain and care of the
terminally ill
• Role in chronic non-cancer pain is more
controversial
• No specific studies have been performed in the
elderly
• Decision to begin long term opioid therapy in
chronic, non-cancer pain “must be weighed
carefully”
• Most of the literature on opioid therapy consists
of reports of surveys and uncontrolled case series
• Most find that chronic pain can be controlled
with nonescalating doses of opiates – up to 6
years of rx, 180 mg morphine
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Function is improved by pt report
Cognitive function is preserved
Ability to drive or operate machinery is preserved
High drop out due to side effects (25%)
• Establish diagnosis
• Confirm inadequacy of nonopioid and
nonmedical treatments
• Ensure that the balance of risk and benefit
favors treatment
• Explain benefits and risks and clinic’s
monitoring policies
• Establish treatment goals
• Request written consent or contract, when
necessary
Side effects
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Constipation
Nausea, vomiting
Sedation
Impaired judgment
Impaired psychomotor function
Respiratory depression
Hypotension
Myoclonus
GU
Pruritus
• Constipation
– Fluids, fiber, stool softener, cathartic
– methylnaltrexone
• Sedation
– Methylphenidate, modafinil
• Dosing – no universal agreement
– Start with lowest dose of short acting preparation
– Up titrate no more often than weekly
– Convert to sustained release formulations when
possible (25-50% of 24 hour total)
– Monitor for efficacy, side effects
“Blue Sheet”
Practice Partner Template
– Is patient currently taking an opioid medication? <yes>
<no>
– If yes is clicked, then:
• Is patient taking any adjuvant pain medications? <yes>
<no>
• Does patient report side effects? <yes> <no>
• Based on pain assessment, plan to: (pick list of :)
– Increase dosage of opioid pain medication
– Decrease dosage of opioid pain medication
– Add adjuvant pain medication
– No changes planned to pain medication regimen
Pain Management ACOVE starts on:
October 24, 2011