32
Principles of Pain Management
R. Morgan Bain
Learning Objectives
Upon completion of the chapter, the student will be able to:
1. Understand the pathophysiology of pain.
2. Know the steps on how to obtain an adequate pain history.
3. Identify the different types of medications used for treating pain, and their indications and limitations.
4. Appreciate that pain is multifactorial and often requires multiple modalities of treatment for improvement.
573 Material in this chapter is based on the following chapter in Cassel CK, Leipzig RM, Cohen HJ, Larson EB, Meier DE, eds. Geriatric Medicine: An Evidence- Based Approach, 4th ed. New York: Springer, 2003: Ferrell BA. Acute and Chronic Pain, pp. 323–342. Selections edited by R. Morgan Bain.
Case (Part 1)
Mr. Peters is a 70-year-old man with a medical history of essential hypertension and hyperlipidemia for which he has been under your care for the past 7 years. He takes a diuretic medication for his hypertension and a hepatic hydroxymethylglutaryl coenzyme A (HMG-CoA) reduc- tase inhibitor for his high cholesterol. He is married and has three adult children and seven grandchildren. He is a retired accountant and enjoys volunteering at his local hospital.
Mr. Peters has had complaints of pain in his left knee after playing tennis on occasion, which is relieved with acetaminophen. Generally, he has been in good health lately.
What are some potential causes of Mr. Peters’ knee pain?
General Considerations
Pain is one of the most common symptoms of disease in older persons.
Second only to symptoms of upper respiratory tract infections, it is one of the most common complaints in physicians’ offi ces.
The approach to pain assessment and management is different in elderly versus younger persons (1). Older persons may underreport pain for a variety of reasons (2), despite functional impairment, psychological dis- tress, and needless suffering related to pain. They often present with con- current illnesses and multiple problems, making pain evaluation and treatment more diffi cult. Elderly persons have a higher incidence of side effects to medications and higher potential for complications and adverse events related to many treatment procedures. Despite these challenges, pain can be effectively managed in most elderly patients. Moreover, clini- cians have an ethical and moral obligation to prevent needless suffering and provide effective pain relief, especially for those near the end of life (3).
Age-Associated Changes Related to Pain Perception
Age-related changes in pain perception have been a topic of interest for many years. Elderly persons have been observed to present with painless myocardial infarction and painless intraabdominal catastrophes.
The extent to which these observations are attributable to age-related changes in pain perception remains uncertain (4,5). Table 32.1 summarizes anatomic and neurochemical changes associated with pain perception in aging. Unfortunately, most of these fi ndings are not specifi c to pain, and changes in pain perception related to these fi ndings remain poorly defi ned.
Acute Pain
Acute pain is often defi ned by its distinct onset, obvious cause, and short duration. Trauma, burns, infarction, and infl ammation are examples of pathologic processes that can result in acute pain. Acute pain is often associated with autonomic nervous system signs including tachycardia, diaphoresis, or elevation in blood pressure (6). The presence of acute pain often indicates an acute injury or acute disease; and the intensity of acute pain often indicates the severity of injury or disease. Thus, acute pain should trigger an urgent search for an underlying cause that might be life threatening or require immediate intervention.
Chronic Pain
Chronic pain is usually defi ned by its persistence beyond an expected time frame for healing. The International Association for the Study of Pain defi nes chronic pain as lasting more than 3 months (7). Intensity of chronic pain is often out of proportion to the observed pathology and often associated with prolonged functional impairment, both physical and psychological.
Autonomic signs are often absent or exhausted. Underlying causes of chronic pain are often associated with chronic disease and are less curable (7).
Chronic pain is often more diffi cult to manage because the underlying cause is less remedial and many treatment strategies are short lived, diffi - cult to maintain, or associated with long-term side effects. Chronic pain usually requires a multidimensional approach to treatment, including use of both analgesic drug and nondrug strategies, with attention to sensory, emotional, and behavioral components of the pain experience.
Table 32.1. Age-related changes in pain perception (4)
Component Age-related change Comments
Pain receptors • 50% decrease in Pacini’s corpuscles Few studies largely limited
• 10–30% decrease in Meissner’s/ to skin Merkel’s disks
• Free nerve endings—no age change
Peripheral • Myelinated nerves Evidence of change in pain nerves —Decreased density function is lacking;
—Increase abnormal/degenerating fi ndings are not specifi c
fi bers to pain
—Slower conduction velocity
• Unmyelinated nerves
—Decreased number of large fi bers (1.2–1.6 µm)
—No change in small fi bers (0.4 µm) —Substance P content decreased
Central nervous • Loss in dorsal horn neurons Findings not specifi c to system —Altered endogenous inhibition, pain
hyperalgesia
• Loss of neurons in cortex, midbrain, brainstem
—18% loss in thalamus
—Altered cerebral evoked responses
—Decreased catecholamines, acetylcholine,
GABA, 5-HT
—Endogenous opioids—mixed changes
—Neuropeptides—no change
GABA, γ-aminobutyric acid; 5-HT, 5-hydroxytryptamine (serotonin), µm, micrometer.
Source: Adapted from Gibson SJ, Helme RD. Age differences in pain perception and report: a review of physiological, psychological, laboratory and clinical studies. Pain Rev 1995;2:111–137. Reprinted by permission of Sage Publications Ltd. Copyright 1995, SAGE Publications. Reprinted as appears in Ferrell BA. Acute and Chronic Pain, pp. 323–342. In:
Cassel CK, Leipzig RM, Cohen HJ, et al., eds. Geriatric Medicine, 4th ed. New York:
Springer, 2003.
Classifi cation Based on Pathophysiology
The classifi cation of pain by pathophysiologic mechanisms may help clini- cians choose and target pain management strategies more effectively. The American Geriatrics Society Panel on Chronic Pain identifi ed four basic pathophysiologic pain mechanisms that have important implications for choosing pain management strategies (Table 32.2) (8).
Case (Part 2)
Today, Mr. Peters presents to your offi ce with complaints of pain in his left fl ank, which started a couple of days ago and is making it diffi cult to sleep or take a deep breath. His blood pressure is 145/90 mmHg, pulse 95/min, and he is afebrile. He appears to be in much discomfort and is holding his hand against his left chest. Upon examination of his chest, you notice a vesicular rash with crusting that appears in a dermatomal distribution on his left fl ank that does not cross the midline. You fi nd out that Mr. Peters had an episode of chickenpox as a young child.
What is the most possible diagnosis?
What is the mechanism of Mr. Peters’s pain?
Table 32.2. Pain classifi cation based on pathophysiology (8) I. Nociceptive pain (somatic and visceral)
a. Trauma (and burns) b. Ischemia
c. Infl ammation (e.g., infection, infl ammatory diseases, arthritis)
d. Mechanical deformity (e.g., tissue strain, swelling, tumor, physical distortion) e. Myalgias (e.g., myofascial pain syndromes)
II. Neuropathic pain a. Peripheral nerves i. Diabetic neuralgia
ii. Viral neuralgia (e.g., postherpetic neuralgia)
iii. Traumatic neuralgia (e.g., postsurgical neuralgia, phantom limb) iv. Trigeminal neuralgia
b. Central nervous system i. Post-thalamic stroke pain
ii. Myelopathic pain (e.g., multiple sclerosis) c. Sympathetic nervous system
i. Refl ex sympathetic dystrophy
ii. Causalgia (e.g., complete regional pain syndromes) III. Mixed or undetermined pathophysiology
a. Chronic recurrent headaches
b. Vasculopathic pain syndromes (e.g., vasculitic pain syndromes)
IV. Psychologically based pain syndromes (e.g., somatization disorders, hysterical reactions)
Source: Adapted from American Geriatric Society Panel on Chronic Pain in Older Persons.
The management of chronic pain in older persons. J Am Geriatr Soc 1998;46:635–651, with permission from Blackwell Publishing Ltd. Reprinted as appears in Ferrell BA. Acute and Chronic Pain, pp. 323–342. In: Cassel CK, Leipzig RM, Cohen HJ, et al., eds. Geriatric Medicine, 4th ed. New York: Springer, 2003.
Nociceptive Pain
Pain problems that result largely from stimulation of pain receptors are called nociceptive pain (9). Nociceptive pain may arise from tissue injury, infl ammation, or mechanical deformation. Examples include trauma, burns, infection, arthritis, ischemia, and tissue distortion. Pain from noci- ception usually responds well to common analgesic medications.
Neuropathic Pain
Neuropathic pain results from pathophysiologic processes that arise in the peripheral or central nervous system (10,11). Examples include diabetic neuralgia, postherpetic neuralgia, and posttraumatic neuralgia (postampu- tation or “phantom limb” pain). In contrast to nociceptive pain, neuro- pathic pain syndromes have been found to respond to nonconventional analgesic medications such as tricyclic antidepressants and anticonvulsant drugs.
Mixed Pain Syndrome
Mixed pain syndromes are often thought to have multiple or unknown pathophysiologic mechanisms. Treatment of these problems is more prob- lematic and often unpredictable. Examples include recurrent headaches and some vasculitic syndromes.
Psychologically Based Pain Syndromes
Psychologically based pain syndromes are those with psychological factors that play a major role in the pain experience (12). Examples include somatoform disorders and conversion reactions. These patients may benefi t from specifi c psychiatric intervention, but traditional pain strategies are probably not indicated.
Epidemiology
The precise incidence and prevalence of pain in older populations is not known. In general, the most common causes of pain in elderly persons is probably related to musculoskeletal disorders such as back pain and arthritis. Neuralgia is common, stemming from common diseases, such as diabetes or herpes zoster, and trauma, such as surgery, amputation, and other nerve injuries. Nighttime leg pain (e.g., cramps, restless legs) is also common, as is claudication. Cancer, although not as common as ar - thritis, is a cause of severe pain that is distressing to patients, families, and staff.
Pain is also common in nursing homes. It has been suggested that 45%
to 80% of nursing home residents may have substantial pain (13). Many of these patients have multiple pain complaints and multiple potential sources of pain.
Pain is associated with a number of negative outcomes in elderly people.
Depression, decreased socialization, sleep disturbance, impaired ambula- tion, and increased health care utilization and costs have all been associ- ated with the presence of pain in older people. Older patients rely heavily on family and other caregivers near the end of life. For these patients and their caregivers, pain can be especially distressing. Pain can have a sub- stantial impact on caregiver strain and caregiver attitudes (14).
Case (Part 3)
A diagnosis of herpes zoster (shingles) is made. Mr. Peters tells you that the pain is severe and that it is limiting his ability to dress himself as well as perform any of his household chores. He tried taking acetamino- phen to help with the pain but it was ineffective.
What other questions are necessary to get an adequate pain history from Mr. Peters?
Diagnostic Evaluation
Symptoms and Signs
Assessment of pain should begin with a thorough history and physical examination to help establish a diagnosis of underlying disease and form a baseline description of pain experiences. The history should include questions to elicit the following: when the pain started; what events or ill- nesses coincided with the onset; where it hurts (location) and how it feels (character); what are the aggravating and relieving infl uences; and what treatments have been tried. Past medical and surgical history is important to identify coexisting disease and previous experience with pain and anal- gesic use. The review of systems should focus on the musculoskeletal and nervous system. Any history of trauma should be thoroughly investigated because falls, occult fractures, and other injuries are common in this age group. In this setting, care must be taken to avoid attributing acute pain to preexisting conditions. Complicating pain assessment is the fact that chronic pain does fl uctuate with time. Injuries from minor trauma and acute disease, such as gout or calcium pyrophosphate crystal arthropathy, can be easily overlooked. Finally, many older persons do not use the word pain but may refer to their problems as “hurting,” “aching,” or some other
description. It is important to probe for and identify pain in the patient’s own words so that references for subsequent follow-up evaluations are clearly established (15).
A physical examination should confi rm any suspicions suggested by the history. Because of the frequency with which problems are often identifi ed, the physical exam should concentrate on the musculoskeletal and nervous systems. Tender points of infl ammation, muscle spasm, and trigger points should be sought. Observation of abnormal posture, gait impairment, and limitations in range of motion may trigger a need for physical therapy and rehabilitation. Evidence of kyphosis, scoliosis, and abnormal joint align- ments should be identifi ed. A systematic neurologic exam is also important to identify potential sources of neuropathic pain. Focal muscle weakness, atrophy, abnormal refl exes, or sensory impairments may indicate periph- eral or central nervous system injury.
It is important to assess functional status to identify self-care defi cits and formulate treatment plans that maximize independence and quality of life. Functional status can also represent an important outcome measure of overall pain management. Functional status can be evaluated from information taken from the history and physical examination, as well as the use of one or several functional status scales validated in elderly people.
A brief psychological and social evaluation is also important. Depres- sion, anxiety, social isolation, and disengagement are all common in patients with chronic pain. There is a signifi cant association between chronic pain and depression, even when controlling for overall health and functional status. Therefore, assessment should include routine screening for depres- sion. Psychological evaluation should also include consideration of anxiety and coping skills. Anxiety is common among patients with acute and chronic pain and requires extra time and frequent reassurance from health care providers. Chronic pain often requires effective coping skills for anxiety and other emotional feelings that can be learned (16). For those with signifi cant psychiatric symptoms, referral for formal psychiatric evalu- ation and management may be required.
Case (Part 4)
On the Verbal 0–10 Scale, Mr. Peters rates his pain on his side as a 9/10 at present. After taking the acetaminophen, the pain in his side only decreased to 8/10. He says that the pain in his knee at its worse is usually a 4/10.
What are some other methods/scales for characterizing pain severity?
Pain Assessment Scales
Pain assessment is the most important part of pain management. Accurate pain assessment is important to identify the underlying source and associ- ated physiologic pain mechanisms in order to choose the most effective treatment and maximize patient outcomes. Pain management is most effec- tive when the underlying cause of pain has been identifi ed and treated defi nitively. Inherent in pain assessment is the need to evaluate acute pain that may indicate life-threatening injury and distinguish this from exacer- bations of chronic pain. For chronic pain in which the cause is not revers- ible or only partially treatable, a multidimensional or multidisciplinary evaluation may be required. Among those with cognitive impairment or diffi culty reporting pain, other clinicians, family, and caregivers may be helpful in providing a more accurate description.
Pain scales can be grouped into multidimensional and unidimensional scales. In general, multidimensional scales with multiple items often provide more stable measurement and evaluation of pain in several domains. At the same time, multidimensional scales are often long, time- consuming, and can be diffi cult to score at the bedside, making them dif- fi cult to use in a busy clinical setting.
Unidimensional scales consist of a single item that usually relates to pain intensity alone. These scales are usually easy to administer and require little time or training to produce reasonably valid and reliable results. They have found widespread use in many clinical settings to monitor treatment effects and for quality assurance indicators. Table 32.3 describes some unidimensional scales that are commonly used. Unidimensional scales may be more useful in assessing pain at the moment while evaluating changes in pain reports over time, much the way vital signs are used. This is espe- cially true for those with some cognitive impairment.
Case (Part 5)
After much discussion, Mr. Peters agrees to be admitted to the hospital for acute pain management. You feel that his pain is too severe for him to be effectively treated as an outpatient. You start him on acyclovir plus intravenous morphine. The morphine is to be administered around the clock every 4 hours with a PRN dose every hour as needed for breakthrough pain.
Would treating Mr. Peters’s pain with a nonsteroidal antiinfl amma- tory drug (NSAID) be a more appropriate fi rst-line therapy than an opioid?
What are the common side effects of opioids?
Table 32.3. Unidimensional scales for pain measurement (38) Scale DescriptionValidityReliabilityAdvantages Disadvantages References Visual analog100-mm line; verticalGoodFairContinuous scaleRequires pencilClinical Practice or horizontaland paper Guidelines (7,8,39) Present pain6-point 0–5 scale withGoodFairEasy to understand, Usually requires Melzack, 1975 (28,40) intensity word descriptors word anchors visual cue (subscale of McGill decrease clustering Pain Questionnaire) toward middle ofscale Graphic pictures Happy faces; othersFairFairAmusingRequires visionHerr et al. (14,41) and attention Sloan Kettering7 words randomlyGoodFairEase of administrationRequires visual cueFerrell et al. (13,42,43) pain card distributed on a card Verbal 0–10“On a scale of 0 to 10, GoodFairProbably easiest to use Requires hearing Ferrell et al. (13,42) Scale if 0 means no pain and 10 means the worst pain you can imagine, how much is your pain now?” Source: Adapted from Ferrell BA. Pain. In: Osterweil D, Brummel-Smith K, Beck JB, eds. Comprehensive Geriatric Assessment. New York: McGraw-Hill, 2000:390, with permission from The McGraw-Hill Companies. Reprinted as appears in Ferrell BA. Acute and Chronic Pain. In: Cassel CK, Leipzig RM, Cohen HJ, et al., eds. Geriatric Medicine, 4th ed. New York: Springer, 2003.
Management Considerations
Acute and Perioperative Pain Management
The treatment of acute pain relies largely on short-term use of analgesic medications and resolution of the underlying cause. The World Health Organization (WHO) recommends that the treatment of acute pain be based on the intensity of the pain (6,17). Pain of mild intensity usually responds to nonopioid drugs used alone or in combination with other physical and cognitive-behavioral interventions. Pain of moderate intensity often requires more intensive efforts, such as weak opioids or low doses of more potent opioid drugs. Many of these drugs are compounded with NSAIDs or acetaminophen to achieve enhanced relief, with only modest exposure to the side effects of opioids. Severe pain usually requires potent opioid analgesic medications given alone or in combination with other analgesic strategies. For severe trauma or postoperative pain, intermittent intravenous, continuous intravenous, or spinal anesthesia may provide faster and more continuous pain relief. Table 32.4 provides an outline of acute pain control options for mild, moderate, and severe pain.
Although initially designed as a stepwise approach to cancer pain man- agement, the WHO approach has become an acceptable approach to all pain with a few caveats. First, it is important to remember that the model does not require that strong opioids be withheld until after other treat- ments have failed. When patients present with severe pain, they should be treated initially with strong medications. Second, when pain rapidly esca- lates from mild to severe, analgesia should be rapidly escalated to strong opioids, with or without other combined strategies. Third, adjuvant drugs and combined treatments should be used early for mild to moderate pain, Table 32.4. Acute pain control options
Mild pain
• Administration of acetaminophen or NSAIDs
• Cognitive-behavioral strategies (relaxation, distraction, etc.) • Physical agents (cold, heat, massage, etc.)
• Combined strategies Moderate pain
• Low-dose or low-potency opioids
• Combinations of acetaminophen or NSAIDs with low-dose or low-potency opioids • Combined strategies
Severe pain
• Potent opioid analgesics (intermittent or around the clock) • Continuous infusions of opioid analgesics (e.g., PCA) • Neural blockade (intermittent or continuous)
• Spinal anesthesia (e.g., epidural anesthesia, intermittent or continuous) • Combined strategies
NSAID, nonsteroidal antiinfl ammatory drug; PCA, patient-controlled analgesia.
Source: Adapted from Acute Pain Management Guideline Panel. Acute Pain Management:
Operative Medical Procedures and Trauma. Clinical Practice Guideline. AHCPR Pub 92- 0032. Rockville, MD: Agency for Health Care Policy and Research, Public Health Service, U.S. Department of Health and Human Services; 1992. Reprinted as appears in Ferrell BA.
Acute and Chronic Pain, pp. 323–342. In: Cassel CK, Leipzig RM, Cohen HJ, et al., eds.
Geriatric Medicine, 4th ed. New York: Springer, 2003.
especially those of the neuropathic type. Finally, when patients present with acute pain, even though establishing a diagnosis is a priority, symp- tomatic pain treatment should be initiated while investigations are pro- ceeding. It is rarely justifi ed to defer analgesia until a diagnosis is made.
In fact, a comfortable patient is better able to cooperate with diagnostic procedures.
Chronic Pain Management
Chronic pain management often requires a multimodal approach of drug and nondrug pain management strategies (8). Although analgesic medica- tions are the most common strategy employed, the concurrent use of cogni- tive-behavioral therapy and other nondrug strategies may be helpful to reduce long-term reliance on medications alone.
In general, chronic pain is often more diffi cult to relieve than acute pain.
Patients should be given an expectation of pain relief, but it is unrealistic to suggest or sustain an expectation of complete relief for some patients with chronic pain. The goals and trade-offs of possible therapies need to be discussed openly. Sometimes a period of trial and error should be anticipated when new medications are initiated and titration occurs. Review of medications, doses, use patterns, effi cacy, and adverse effects should be a regular process of care (8). Ineffective drugs should be tapered and discontinued.
It is appropriate to consider economic issues and make balanced deci- sions while basic principles of pain assessment and treatment are followed.
Health care professionals should be aware of the costs and fi nancial barri- ers patients and families may encounter with the strategies often pre- scribed. These issues include limited Medicare reimbursement, limited formularies, delays in referrals in some managed care environments, delays from mail-order pharmacies, and limited availability of opioid medications in some pharmacies.
Case (Part 6)
After spending a week in the hospital to manage his acute pain, Mr.
Peters was discharged. His lesions were clearing up and the pain had been substantially reduced. Upon repeat pain assessment, he rated the pain as 3/10 with occasional fl ares to 5/10. He was given a prescription for a combination analgesic to be taken every 4 hours as needed.
Four months later, despite regular offi ce visits and continued use of analgesics, Mr. Peters states that the pain in his left fl ank is still persis- tent and bothersome.
What is the mechanism for his pain now?
What other types of medications may be helpful in treating the pain?
Pharmacologic Approach to Pain Management
Any patient who has pain that impairs functional status or quality of life is a candidate for analgesic drug therapy (8). Analgesic medications are safe and effective for elderly people. Dosing for most patients requires beginning with low doses with careful upward titration, including fre- quent reassessment for optimum pain relief and management of side effects.
The least invasive route of drug administration should be used. Some drugs can be administered from a variety of routes, such as subcutaneous, intravenous, transcutaneous, sublingual, and rectal. The oral route is pref- erable because of its convenience and relatively steady blood levels pro- duced. Intravenous bolus provides the most rapid onset and shortest duration of action, which may require substantial labor, technical skill, and monitoring. Subcutaneous and intramuscular injection, although com- monly used, has the disadvantages of wider fl uctuations in absorption and rapid fall-off of action compared to oral routes. Transcutaneous, rectal, and sublingual routes are also more diffi cult to predict but may be essential for those with diffi culty swallowing (8).
Timing of medications is also important. Fast-onset, short-acting anal- gesic drugs should be used for episodic pain on an as-needed schedule. For continuous pain, medications should be provided around the clock. In these situations, a steady-state analgesic blood level is more effective in maintaining comfort. Long-acting or sustained-release preparations should be used only for continuous pain. Most patients with continuous pain also need fast-onset short-acting drugs for breakthrough pain. Breakthrough pain includes (1) end-of-dose failure as the result of decreased blood levels of analgesic with concomitant increase in pain prior to the next scheduled dose; (2) incident pain, usually caused by activity that can be anticipated and pretreated; and (3) spontaneous pain, common with neuropathic pain that is often fl eeting and diffi cult to predict (8).
Acetaminophen
Acetaminophen is the drug of choice for elderly persons with mild to mod- erate pain, especially that of osteoarthritis and other musculoskeletal prob- lems (8). As an analgesic and antipyretic, acetaminophen acts in the central nervous system to reduce pain perception. Despite the lack of antiinfl am- matory activity, studies have shown that acetaminophen is as effective as ibuprofen for chronic osteoarthritis of the knee (18). Given in a dose of 650 to 1000 mg four times a day, it remains the safest analgesic medication compared to traditional NSAIDs and other analgesic drugs for most patients. Unfortunately, acetaminophen overdose can result in irreversible hepatic necrosis. Therefore, the maximum daily dose should never exceed 4000 mg per day (8).
Nonsteroidal Antiinfl ammatory Drugs
Nonsteroidal antiinfl ammatory drugs (NSAIDs) have analgesic activity both peripherally and centrally. They are potent inhibitors of prostaglan- din synthesis, which have effects on infl ammation, pain receptors, and nerve conduction, and may have central effects, as well (19).
Nonspecifi c inhibitors of cyclooxygenase (COX) enzymes (most older NSAIDs) are still appropriate for short-term use in infl ammatory arthritic conditions such as gout, calcium pyrophosphate arthropathy, acute fl are-ups of rheumatoid arthritis, and other infl ammatory rheumatic conditions. They have also been reported to relieve the pain of headache, menstrual cramps, and other mild-to-moderate pain syndromes. These drugs can be used alone for mild-to-moderate pain or in combination with opioids for more severe pain. They have the advantage of being non–habit forming. Individual drugs in this class vary widely with respect to antiinfl ammatory activity, potency, analgesic properties, metabolism, excretion, and side-effect pro- fi les. Moreover, it has been observed that failure of response to one NSAID may not predict the response to another. A disadvantage of NSAIDs is that, unlike opioids, they all demonstrate a ceiling effect, that is, a level at which increased dose results in no further increase in analgesia. A large number of NSAIDs are now available; however, there is no evidence to support a particular compound as the NSAID of choice. Several are available over-the- counter without a prescription. Table 32.5 lists selected NSAIDs for pain.
High-dose NSAIDs for long periods of time should be avoided in elderly patients (8). Of major concern is the high incidence of adverse reactions, including gastrointestinal bleeding (20), renal impairment (21), and bleed- ing diathesis from platelet dysfunction. The concomitant use of misopros- tol, high-dose histamine-2 receptor antagonists, and proton pump inhibitors is only partially successful at reducing the risk of signifi cant gastrointestinal bleeding associated with NSAID use (22–24). Also, the side-effect profi les of gastroprotective drugs in this population must be weighed against their limited benefi ts (25). For those with multiple medical problems, NSAIDs are associated with increased risk of drug–drug and drug–disease interac- tions; NSAIDs may interact with antihypertensive therapy (26). Thus, the relative risks and benefi ts of NSAIDs must be weighed carefully against other available treatments for older patients with chronic pain problems.
For some patients, chronic opioid therapy, low-dose or intermittent cortico- steroid therapy, or other nonanalgesic drug strategies may have fewer life- threatening risks compared to long-term NSAID use (8) (see Chapter 3:
Geriatric Pharmacology and Drug Prescribing for Older Adults, page 39).
Opioid Analgesic Medications
Opioid analgesic medications act by blocking receptors in the central nervous system (brain and spinal cord), resulting in a decreased perception of pain. Selected opioid analgesic medications are listed in Table 32.6.
Table 32.5. Selected nonsteroidal antiinfl ammatory drugs for pain Drug Maximum doseDescriptionComments Relafen (Nabumetone) 2000 mg/24 h (q 24 h dosing) Partially Cox-2 selective; gastric toxicityAvoid maximum dose for prolonged periods may be less; occasionally requires q 12 h dosing Aspirin 4000 mg/24 h (q 4–6 h dosing) Prototype NSAID Salicylate levels may be helpful in monitorin Salsalate (Disalcid) 3000 mg/24 h (q 6–8 h dosing) Hydrolyzed in small intestine to aspirin Elderly may require dose adjustment downwa to avoid salicylate toxicity; salicylate levels may be helpful in monitoring Ibuprofen (Motrin by 2400 mg/24 h (q 6–8 h dosing) Gastric, renal, and abnormal platelet Avoid high doses for prolonged prescription; Advil, function may be dose dependent;periods of time Nuprin, and others constipation, confusion, and headaches OTC) may be more common in older persons Difl unisal (Dolobid) 1000 mg/24 h maximum doseRelatively good analgesic properties, but Dose may need downward adjustment for sm Loading = 1000 mg then 500 q requires loading dosepatients or frail elderly 12 h; or 750 mg then 250 mg q 8 h in small patients or frail elderly Sulindac (Clinoril) 400 mg/24 h (q 12 h dosing) Same as ibuprofenSame as ibuprofen Naproxen (Naprosyn by 1000 mg/24 h (q 8–12 h dosing) Same as ibuprofen; may require a loading Same as ibuprofen prescription; Aleve dose and others OTC) Choline magnesium 5500 mg/24 h (q 12 h dosing) Lower effect on platelet functionSalicylate levels may be helpful to avoid tox trisalicylate (Trilisate) Indomethacin (Indocin) 200 mg/24 h (q 8–12 h dosing) Extremely high toxicity in frail elderly; Keep dose to a minimum (25 mg q 8 h)and should be reserved for acute for short-term use only; avoid use for infl ammatory conditions (e.g., gout, etc.) osteoarthritis or other noninfl ammatory problems Ketorolac (Toradol) IM: 120 mg/24 h (30–60 mg loading Substantial gastrointestinal toxicity as Duration of treatment limited because of hig dose; followed by half the loading well as renal and platelet dysfunction; toxicity; reduce dose in half for those<50 dose (15–30 mg q 6 h limited torelatively high postoperative or >65 years of age not more than 5 days) complications have been documented PO: 60 mg/24 h (q 6 h dosing limited to not more that 14 days) Note: Limited number of examples are provided. For comprehensive lists of other available NSAIDs and a host of brand names, clinicians should consult o sources. COX, cyclooxygenase; IM, intramuscular injection; OTC, over-the-counter or available without prescription; PO, per oral route or by mouth. Source: Ferrell BA. Acute and Chronic Pain. In: Cassel CK, Leipzig RM, Cohen HJ, et al., eds. Geriatric Medicine, 4th ed. New York: Springer, 2003.
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