Pearls in Pain Management

From Pain Management for the Primary Care Practitioner: What You Need to Know, presented by
the University of Wisconsin School of Medicine and Public Health, October 2008

Educational Objectives

The goal of this program is to improve management of pain and to review rehabilitation modalities in pain states. Af­ter hearing and assimilating this program, the clinician will be better able to:

Describe risks and benefits associated with use of nonsteroidal anti-inflammatory drugs.

Target specific pain conditions such as diabetic neuropathy and fibromyalgia with appropriate medications.

List risks and benefits of common adjuvant
analgesics.

Identify effective uses of ultrasonography and transcutaneous electrical nerve stimulation for pain.

Counsel patients about rehabilitating with exercise and strength training.

Faculty Disclosure

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any per­sonal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the faculty and plan­ning committee reported nothing to disclose.

Acknowledgements

Drs. Rudin and Leonard spoke in Madison, WI, at Pain Management for the Primary Care Practitioner: What You Need to Know, presented October 24-25, 2008, by the University of Wisconsin School of Medicine and Public Health. The Audio-Digest Foundation thanks the speakers and the University of Wisconsin School of Medicine and Public Health for their cooperation in the production of this program.

Nonopioids for Pain

Nathan J. Rudin, MD, Associate Professor of Orthopedics and Rehabilitation, and Medical Director, Pain Treatment and Research Center, University of Wisconsin School of Medicine and Public Health, Madison

Basic principles: different analgesics work at different points in pain pathway; target medications to type of pain  and severity; treat early, even preemptively, to avoid hypersensitization of nervous system and chronic pain; combine analgesics to target multiple pain mechanisms; watch for side effects

Nonsteroidal anti-inflammatory drugs (NSAIDs): nonspecific cyclooxygenase (COX) inhibitors erode protection of gastroduodenal mucosa and interfere with platelet function; early use of COX-2 inhibitors may reduce need for other analgesics; advantages  —  no mental clouding or respiratory depression; usually well tolerated (acutely); may reduce need for opioids; efficacious for mild to moderate pain; disadvantages  —  gastrointestinal (GI) toxic­ity; nephrotoxicity; bleeding; asthma; hypertension; may interfere with connective tissue synthesis; ceiling effect (monitor for maximum dose before adverse effects); increased risk for cardiovascular (CV) and cerebrovascular disease  —increased tendency to clot; higher risk for mortality and myocardial infarction (MI) in patients with previous MI; in patients without clear CV risk factors, short-term benefits may outweigh risks; long-term effects uncertain; since aspirin inhibits platelet function, it does not share same risks

Acetaminophen: mild peripheral anti-inflammatory action; effective analgesic and antipyretic; hepatotoxicity with 200 to 250 mg/kg; in patients with known renal disease, combination with other NSAIDs increases risk for anal­gesic nephropathy; maximum adult dose 4000 mg/day

Celecoxib: sometimes used preferentially in patients with high GI risk, but not found superior for pain relief; be cautious in patients with CV or stroke risk factors; short-term treatment preferable

Diclofenac: topical NSAID; transdermal system (patch) approved by Food and Drug Administration (FDA) for acute pain due to minor strains, sprains, and contusions; gel approved for peripheral joint osteoarthritis (OA); side effects include pruritus, burning, and dermatitis; GI side effects no different from placebo; no evidence of superiority to oral analgesics; expensive

NSAIDs in chronic pain: NSAIDs useful for OA and inflammatory conditions; benefit less clear in fibromyalgia and myofascial pain; avoid overuse; watch for drug interactions

Adjuvant analgesics: drugs with primary applications other than pain (mostly off-label); effective for neuropathic pain, complex regional pain syndrome (CRPS), fibromyalgia, and migraine and other head disorders

Tricyclic antidepressants (TCAs): potentiate actions of biogenic amines (eg, norepinephrine, serotonin) in central nervous system (CNS), resulting in less pain, depression, and anxiety; shown effective in neuropathic pain; choose based on patient presentation, history, comorbidities, and side effects; secondary amines (eg, nortriptyline) may be better tolerated than tertiary amines (eg, amitriptyline); better analgesic effects seem associated with worse side ef­fects; side effects  —sedation (may be helpful for sleep difficulties); anticholinergic effects (eg, dry mouth, blurred vision, urinary retention, constipation); weight gain; cardiac arrhythmia (especially atrial tachycardia) can occur (contraindicated in patients with atrial fibrillation); dosing  —  not well tolerated by patients with hypersensitive ner­vous systems; start with low dose (eg, 5-10 mg of amitriptyline) then titrate up incrementally; discuss side effects; assess benefit after several weeks; monitor therapeutically; taper gradually when stopping

Trazodone: serotonin antagonist at low doses, serotonin agonist at high doses; highly sedating and anticholinergic (not recommended for elderly patients and patients prone to delirium or dementia); watch for orthostasis and pria­pism

Selective serotonin reuptake inhibitors (SSRIs): less sedating than TCAs (may be alerting); second- and third-line therapy for neuropathic pain; first-line therapy for depression and anxiety; moderate dose can be coadministered with modest dose of TCA; fluoxetine associated with high incidence of sexual dysfunction; paroxetine can cause extrapyramidal reactions; sertraline; citalopram; escitalopram; none proven analgesic; side effects  —  nausea; diar­rhea; headache; dizziness; anorexia; agitation; sexual dysfunction; many drug interactions; withdrawal syndrome

Other antidepressants: mirtazapine  — sedating; less anticholinergic; venlafaxine  —  may have some analgesic effect; serotonin-norepinephrine reuptake inhibitor (SNRI); bupropion  —  useful for tobacco smoking cessation; not rec­ommended for agitated patients or patients with bipolar disorder; milnacipran  —  undergoing studies; duloxetine  —SNRI; approved for painful diabetic neuropathy and fibromyalgia; start with 20 to 30 mg/day for 1 wk, then 60 mg/day; taper gradually when stopping; many adverse effects; can cause liver irritation

Anticonvulsants: shown effective in neuropathic pain; can cause cognitive impairment and sedation (use with cau­tion); carbamazepine  —  drug of choice for trigeminal neuralgia; effective for peripheral neuropathy, migraine, cen­tral pain syndromes (eg, poststroke pain), and postherpetic neuralgia; can cause dizziness, nausea, vomiting, and sedation; risk for aplastic anemia and hyponatremia; monitor serum levels; lamotrigine  —  blocks sodium channels and inhibits glutamate release; may help reduce central sensitization and pain; useful in trigeminal neuralgia; inter­acts with other anticonvulsants; risk for bone marrow toxicity, rash, and Stevens-Johnson syndrome; contraindi­cated in pregnancy; start at 25 mg at night (sedating) and titrate to £400 mg/day; gabapentin  —  blocks calcium channels; inhibitory CNS effect; well tolerated; start at 100 to 300 mg tid; ³1800 mg/day usually needed; 3600 to 4800 mg/day “good trial”; associated with weight gain and edema; topiramate  —  blocks sodium channels; potenti­ates g-aminobutyric acid (GABA); antagonizes glutamate receptor; side effects include somnolence, fatigue, agita­tion, kidney stones, glaucoma, hypotension, paresthesias, and weight loss; effective for neuropathic pain and migraine; contraindicated in patients with kidney stones or glaucoma; monitor closely; special application for head­ache; pregabalin  —  more selective and easier to titrate than gabapentin; indicated for painful diabetic neuropathy and fibromyalgia; in Europe, indicated for generalized anxiety; start at 50 mg bid or tid; titrate up to 300 mg/day over 1 to 2 wk; adjust dose in renal impairment; taper over ³1 wk; side effects include weight gain, dizziness, som­nolence, edema, headache, infection, and dry mouth; generally well tolerated; monitor patients

Local anesthetics: block sodium channels; reduce ectopic activity; cardiotoxicity main side effect; used for neuro­pathic pain; lidocaine  —  intravenously (IV) or subcutaneously for CRPS or painful neuropathies; useful for refrac­tory pain; transdermal patch useful for postherpetic neuralgia and other cutaneous allodynias; effectiveness for musculoskeletal low back pain, myofascial pain, or knee pain uncertain; weigh risks and benefits; topical cream has short duration; mexiletine  —  oral congener of lidocaine; used in patients who respond to IV lidocaine; antiarrhyth­mic drug (contraindicated in patients with cardiac problems; monitor closely with, eg, electrocardiography); effec­tive for some dysesthetic pain conditions; may have significant GI and cardiac toxicities; clonidine  —  a₂-agonist; antihypertensive agent; helpful in some neuropathic pain, particularly postherpetic neuralgia and CRPS; oral or transdermal; watch for hypotension, rebound hypertension, and dizziness when stopping; attenuates opioid with­drawal symptoms (0.05-0.10 mg/kg £3 times per day, as needed; warn about side effects); capsaicin  —  active ingre­dient in chili peppers; cream useful for inflammatory and some neuropathic conditions; continuous use (eg, 4 times per day) effective; avoid contact with eyes and other mucous membranes; ziconotide (Prialt)  —  derived from cone snail venom; extremely potent calcium channel blocker; effective for neuropathic pain; applied to cerebrospinal fluid through catheter or pump; expensive; limited application

Baclofen and tizanidine: act at spinal cord; used in spinal cord injury, stroke, and traumatic brain injury; may have antineuropathic pain effects; may be useful in treating sleep problems or fibromyalgia (off-label use); may induce muscle relaxation; relieve spasm and spasticity; can cause sedation, orthostasis, and withdrawal symptoms (eg, sei­zure); risk for hepatotoxicity; low doses used at night for patients with sleep disturbances and muscle pain; if well tolerated, titrate up to low bid or tid dosing; perform liver function tests (LFTs) every 6 mo; patients should not drink alcohol

Clonazepam: benzodiazepine; useful for spasticity; long-term use not recommended

Cyclobenzaprine: TCA; effects and side effects similar to those of amitriptyline

Carisoprodol (Soma): muscle relaxant; not recommended; sedative; habit-forming

Serotonin syndrome: due to drug interactions between, eg, SSRIs, trazodone, tramadol, opioids, and triptans; mild  — agitation; tachycardia; shivering; hyperreflexia; moderate  —hyperactive bowel sounds; diaphoresis; increased body temperature; mydriasis; severe  —  hypertension; tachycardia; shock; agitated delirium; hyperthermia; occurs in 14% to 16% of SSRI overdoses; treatment  —  stop precipitating drugs; give benzodiazepine; if patient hyperthermic, ad­mit to intensive care unit (ICU); consider serotonin antagonist

Rehabilitation in Pain States

James W. Leonard, DO, Associate Professor of Rehabilitation Medicine, and Chair, Division of Rehabilitation Medicine, University of Wisconsin School of Medicine and Public Health, Madison

Introduction: identify inflammatory process and mechanical instability; rule out cancer and need for surgery

Collagen and wound healing: prolotherapy  —  irritant-type substance used to cause tissue healing; oxygen-depen­dent

Hot and cold packs: heat  —  home use; maximum physiologic effect with 20 to 30 min of use; cold   —   »80% do bet­ter than with heat; causes vasoconstriction followed by vasodilatation; be cautious in patients with neuropathy and decreased sensation; cold laser for home use expensive and not highly effective

Modalities for pain: ultrasonography  —  ineffective on large surface areas; effective for specific joint problems (eg, epicondylitis) and isolated areas; iontophoresis  —  electrical stimulation drives cortisone solution into skin; helpful for select areas; ineffective for broad peripheral neuropathic pain; lidocaine transdermal patch  —  for headaches and isolated pain; expensive ($5-$6 each)

Electrical stimulation: when added to heat therapy, not shown more effective than heat alone; not shown to restore denervated muscle; can stimulate muscle initially; use alternating current (AC) for live muscle, direct current (DC) for denervated muscle (not commonly used); transcutaneous electrical nerve stimulation (TENS)  —  more effective in specific neuropathic pain; not as effective in broad peripheral neuropathy; effective in postherpetic neuralgia or isolated nerve root; intermittent use can reduce narcotic use; contraindicated in patients with cardiac pacemaker and during first trimester of pregnancy; do not stimulate over carotid sinuses

Hydrotherapy: warm (»92ºF) water pools; effective for multijoint problems, edema, and pain control; whirlpools ap­pear less effective than warm water pools

Traction: home devices appear more effective for cervical than lumbar area; mild transient ischemic attack reported after cervical traction; contraindicated in patients with instability and temporomandibular joint problems (newer units placed at base of skull rather than over jaw); 20 min/day may be effective for patients with osteophytic over­growth in cervical or lumbar spine; £7% of body weight recommended (do not exceed 50% of weight of patient’s head); 10 to 30 min/day recommended; long-term effects with newer units; lumbar traction not as effective; in­verted (45º-60º) traction devices more useful for stenosis than for acute disc problems

Bracing: indicated for lumbar area (especially with stenosis); high compliance in patients >65 yr of age; contraindi­cated in patients with chronic obstructive pulmonary disease or hiatal hernia; good long-term approach when used with other modalities

Mobilization or manipulation: short-term relief with manipulations; contraindications include instability; risky in patients with grade 2 or 3 spondylolisthesis, and in cervical area (may lead to stroke)

Surgery: absolute indications include loss of bowel or bladder control or progressive (or sudden) neurologic deficit; monitor patients with drop foot; larger disc herniations more likely to be reabsorbed spontaneously

Exercise: aerobic exercise most effective; loss of range of motion can be protective mechanism to spine; strength typ­ically regained by 3 mo after injury (after 3 mo, unlikely to return); takes long time to regain endurance; difficult to regain neuromuscular coordination; many patients feel stress and anxiety about exercise; start with 3 to 4 simple exercises in clinic; provide written description (eg, number of repetitions, frequency) and illustrations; follow up; for stenosis, knee and chest exercises open spinal canal; for contained disc herniation, McKenzie extension exer­cises may be helpful; facilitate visits to physical therapist; closed-chain exercises (distal part of joint remains fixed) recommended for specific injuries (eg, knee instability)

Muscle imbalances and gait determinants: lateral slippage can be problematic in older patients with scoliosis; en­courage walking; elderly patients with long-standing back problems develop knee and hip problems due to com­pensation; arch supports may be helpful for patients with flat feet and back pain; check pelvic brim height (correct imbalance if difference in leg length >1 cm); Z-CoiL shoes reduce stress on heel strike when walking; 6-min walk test to measure cardiovascular fitness; treat other peripheral joint diseases; follow bone mineral density in patients with osteoporosis

Exercise recommendations: exercise at 50% to 85% intensity, for 20 to 60 min, 3 to 5 times per week; walkers with seats attached allow patients to walk then take rest periods; reclining (recumbent) exercise bicycles for patients with stenosis; strength training  —  determine maximum load for 10 repetitions (reps); 10 reps at 50%, 10 reps at 75%, and 10 reps at 100%; rest period of 1 to 2 min between each set; establish guidelines to prevent injury; reduce exercise if pain occurs >2 hr after session, same night, or next day

Suggested Reading

No authors listed: Scientific approach to the assessment and management of activity-related spinal disorders. A monograph for clinicians. Report of the Quebec Task Force on Spinal Disorders; Spine 12:S1, 1987; Atlas SJ et al: The Quebec Task Force classification for Spinal Disorders and the severity, treatment, and outcomes of sciatica and lumbar spinal stenosis. Spine 21:2885, 1996; Chapman BL et al: An introduction to physical therapy modalities. Ad­olesc Med State Art Rev 18:11, 2007; Fenwick CM et al: Comparison of different rowing exercises: trunk muscle ac­tivation and lumbar spine motion, load, and stiffness. J Strength Cond Res 23:350, 2009; Jubeau M et al: Effect of electrostimulation training-detraining on neuromuscular fatigue mechanisms. Neurosci Lett 424:41, 2007; Kalso E et al: Opioids in chronic non-cancer pain: systematic review of efficacy and safety. Pain 112:372, 2004; Li LC et al: The efficacy of dexamethasone iontophoresis for the treatment of rheumatoid arthritic knees: a pilot study. Arthritis Care Res 9:126, 1996; Lynch ME: The pharmacotherapy of chronic pain. Rheum Dis Clin North Am 34:369, 2008; Sheel AW et al: Effects of exercise training and inspiratory muscle training in spinal cord injury: a systematic review. J Spinal Cord Medicine 31:500, 2008; Turk DC et al: Fibromyalgia: combining pharmacological and nonpharmaco­logical approaches to treating the person, not just the pain. J Pain 9:99, 2008; Waller B et al: Therapeutic aquatic ex­ercise in the treatment of low back pain: a systematic review. Clin Rehabil 23:3, 2009; Warner TD et al: COX-2 selectivity alone does not define the cardiovascular risks associated with non-steroidal anti-inflammatory drugs. Lan­cet 371:270, 2008.