Pain Management in the Elderly Rog Kyle 10/7/11

1. Pain Management in the ElderlyRog Kyle10/7/11 Aging Q3 ACOVE #10

2. 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

3. Cancer pain • 80% of elderly with cancer report pain • Probably under detected and under treated • Deficiencies • Under documented • Under treated – opioids and non-opioids

4. 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

5. 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

6. Hospitalized patients • No randomized trials • Prospective studies on cancer patients • Underestimate pain • Probably do not assess frequently enough

7. 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

8. 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

9. 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)

10. Pain pathways • Nociceptive fibers – afferent fibers to dorsal horn • Two types • A-delta – sharp pain (fast) • C polymodal – dull pain (slow) • Pathways

12. 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

14. Mechanisms for chronic pain • Peripheral sensitization • Central sensitization • Disinhibition • Desensitization • Ectopic excitability • Structural reorganization • Phenotypic switch of neurons • Primary sensory degeneration

15. 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”

16. Treatment – non drug strategies • Exercise • PT, OT, stretching, strengthening • general conditioning • Physical methods • ice, heat, massage • Cognitive-behavioral therapy

17. Chiropracty • Acupuncture • TENS • Alternative therapies • relaxation, imagery • herbals

18. 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.

19. Non-opioid options • Acetaminophen • Alpha-adrenergic agents • Anticonvulsants • Antidepressants • Muscle relaxants • Neuroleptic agents • NMDA-receptor antagonists • NSAIDs • Oral local anesthetics • Topical analgesics

20. Acetaminophen • First line • 4000mg max • 2000mg recommended with etoh use, liver disease, elderly • Watch for other OTC’s containing acetaminophen

21. Alpha-adrenergics • Epidural clonidine for neuropathic pain (FDA) • Tizanidine outside US

22. 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)

23. Off label • Lamotrigine for HIV neuropathy (and others) • PDN • Carbamazepine, phenytoin, gabapentin • Chronic musculoskeletal pain

24. 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

25. TRICYCLICSSRI OTHER Amitriptyline Fluoxetine Venlafaxine Desipramine Paroxetine Duloxetine* Doxepin Sertraline Trazodone Imipramine Fluvoxamine Bupropion Nortriptyline Citalopram *FDA approved for pain

26. 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

27. Neuroleptics • Fluphenaxine (Prolixin) • Not recommended

28. NMDA receptor antagonists • Scientific promise • Dextromethorphan • Ketamine • Methadone • Memantine • Amitriptyline

29. 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

30. 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)

31. 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

32. 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

33. Tramadol • Mu receptor and SNRI effects • Effective in neuropathic pain, fibromyalgia, OA • Similar side effects to opioids • Seizures, suicide

34. Benzodiazepines • Adjuvant only • Anxiolytic • Limitations • Sedation • Addictive potential • Respiratory depression • Avoid in elderly • Clonazepam • Effective in PHN and myoclonus

35. 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”

36. 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%)

37. Establish diagnosis • Confirm inadequacy of nonopioidand 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

38. Side effects • Constipation • Nausea, vomiting • Sedation • Impaired judgment • Impaired psychomotor function • Respiratory depression • Hypotension • Myoclonus • GU • Pruritus

39. Constipation • Fluids, fiber, stool softener, cathartic • methylnaltrexone • Sedation • Methylphenidate, modafinil

40. 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

41. “Blue Sheet”

42. 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

43. Pain Management ACOVE starts on: October 24, 2011