Aging Q3 ACOVE #10

Pain Management in the ElderlyRog Kyle

10/7/11

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

• 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• 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

• 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• 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– 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 OTHER

Amitriptyline Fluoxetine VenlafaxineDesipramine Paroxetine Duloxetine*Doxepin Sertraline TrazodoneImipramine Fluvoxamine BupropionNortriptyline Citalopram

*FDA approved for pain

Muscle relaxants• Cyclobenzaprine

– 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– 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• 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

Special considerations

• Tolerance– Associative– Non-associative

• Abnormal pain sensitivity– Neuropathic (hyperalgesia, allodynia)

• Sensitization• Desensitization (tolerance)

“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