Pain in Older Adults

Strategies for Success: Pharmacologic Management of Persistent Pain in the Older Adult

 

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CME Information


 

Learning Objectives

After completing this activity, the learner should be better able to

1. Select analgesic therapy in older patients with persistent nonmalignant pain based on the age-related differences between younger and older adults.

2. Initiate comprehensive analgesic treatment strategies, including opioid therapy where warranted, in older patients with persistent nonmalignant pain.

Introduction

The United States is projected to experience a rapid growth in its older population between 2010 and 2050 as the so-called baby boomers cross into this category. According to current projections, by 2030 there will be approximately 71.5 million Americans aged 65 years and older representing nearly 20% of the total population. By 2050, the number of adults aged 65 and older is anticipated to reach 88.5 million, which is more than double the estimated 40.2 million living in the United States right now.[1]

While many older adults are healthy and lead active lives, by the age of 75, many persons are contending with some degree of frailty and chronic illness, while others may have multiple comorbidities.[2] Persons older than 85 years of age are the most likely to have chronic health needs, and this subpopulation of older adults is rapidly expanding. The US Census Bureau projects that this group could grow from 5.3 million (2006 figures) to almost 21 million by midcentury.[3]

Chronic or persistent pain is a common problem in older adults and is often associated with significant physical disability and psychosocial problems. Pain is not a normal part of the aging process, yet it is experienced on a daily basis by a large number of older adults residing in the United States.

The problem of persistent pain among older adults tends to be multifactorial, with, unfortunately, a number of barriers to appropriate assessment and management. Overall, pain in this population is underdiagnosed and consequently undertreated or untreated.[4] Inadequately treated persistent pain has been associated with adverse outcomes that include functional impairment, falls, slow rehabilitation, depression, social isolation, immobility, sleep and appetite disturbances, and greater healthcare use and cost.[2,5-7]

Statistics on the prevalence of pain among older adults vary considerably, ranging from 25% to 80%.[8] It is estimated that 45% to 80% of individuals residing in nursing homes experience persistent pain, while estimates for community dwelling adults are lower—in the range of 25% to 50%. By some estimates, more than 60% of persons aged 75 years and older are afflicted with persistent pain.[9]

The high prevalence of pain and its impact on older adults make it an important public health issue.

Pain in Older Versus Younger Adults

Compared with younger adults, persistent pain appears to be more common and of longer duration in those older than the age of 65 years.[10] Almost 60% of older adults who reported experiencing pain that lasted more than 24 hours stated that it persisted for one year or more compared with 37% of young adults.[10]

Chronic pain tends to manifest differently in older individuals compared with younger adults. While the effects of chronic pain can vary considerably on an individual basis, overall health status is impaired to a lesser degree in older adults compared with younger individuals.[11] Based on their responses to the Treatment Outcomes of Pain Survey, a validated pain-assessment instrument, older adults with chronic pain experience better mental health and less fear avoidance, use less passive coping, and have more life control compared with their younger counterparts. However, older individuals also have more physical limitations affecting the lower body.

Overall, these data indicate that compared with younger adults, individuals aged 60 and older with persistent pain tend to have more physical impairment, particularly physical limitations affecting the lower body, but less of a psychosocial impact.[11] Older patients may tend to be more stoic and accepting of pain than younger individuals because they consider it an inevitable consequence of aging.

Consequently, one could conclude the good news is that older people cope better with pain—but the bad news is that they cope by decreasing function and accepting pain as a consequence of aging. Unfortunately this may lead to a vicious cycle of declining functional status, worsening overall health, and neglect of remedial and treatable conditions, and ultimately resulting in needless suffering.

The prevalence of chronic medical conditions increases with age. An analysis of more than 1.2 million randomly selected Medicare beneficiaries aged 65 and older found that 82% of the cohort had at least one chronic health condition; 65% had more than one.[12] Higher levels of comorbidity have been associated with reports of more severe pain, more depressive symptoms, reduced activity levels, and higher physical impact from pain.[13] Not all comorbid conditions will be associated with pain, but they need to be taken into consideration when developing a pain management plan, and thus can make the process more challenging.

Persistent pain and cognitive impairment are each common in older adults, and especially among institutionalized persons; there is a high prevalence of older adults with dementia and pain or potentially painful conditions.[14] Older adults with cognitive impairment experience pain but are often unable to verbalize it, which represents a major barrier to appropriate assessment and treatment.[14]

Finally, differences in pharmacokinetics and pharmacodynamics between older and younger adults affect pain management. Increasing age is associated with physiologic changes, such as increased body fat, reduced muscle mass, and a reduction in the body’s fluid balance.[15,16] This combination of factors increases the volume of distribution of lipophilic drugs, which in turn delays the onset of action and elimination rate while leaving plasma concentrations unaffected. At the same time, the volume of distribution of hydrophilic drugs declines, which may elevate plasma levels of these agents.

With increasing age comes a reduction in renal and hepatic function, which means progressively diminishing efficacy in drug clearance.[15,16] With reduced hepatic function, the bioavailability of drugs with high first-pass elimination, such as lidocaine and opioid analgesics, will be increased. The presence of chronic hepatic disease will generally require reductions in drug dosages or longer intervals between doses to prevent increased plasma concentrations and a higher risk of side effects.

Reduced renal function, particularly a decrease in the glomerular filtration rate, can increase the half-life of agents that are primarily excreted through the kidneys. Dosing levels may need to be adjusted to prevent drug toxicity, especially drugs with active metabolites, such as morphine.[15,16]

Barriers to Optimal Care

Substantial barriers to the proper management of chronic pain in older adults stem from both the patient and provider perspectives. Patients may fail to report pain because they think that it is a normal part of aging, or their perception of pain may be different from that of younger individuals.[15] They may also withhold reports of pain to avoid additional testing or medication. In particular, they may fear receiving opioids due to heightened concerns about addiction, tolerance, and adverse effects.[17,18]

One survey of cancer patients found that some respondents believed that pain was inevitable, thus indicating that they did not expect medication would be effective.[18] In addition, pain was associated with a worsening of their disease.

Patients who reported difficulties in communicating with their clinicians also reported significantly worse pain, as opposed to those who didn’t. Even in cognitively intact patients, communication problems can arise due to variations in the language used to describe pain. Patients with dementia represent a formidable challenge, as they lack the cognitive ability to effectively describe their pain or the effect of therapeutic intervention.[14,15,19-21] They may react to pain by exhibiting agression or other behavioral changes, which can be misinterpreted as a worsening of their mental functions.

A label of dementia may also bias the interpretation of pain cues of demented patients, and complaints from cognitively impaired patients may be taken for granted. Nygaard and Jarland found that mentally intact nursing home residents were more likely to receive unscheduled pain medication (33%), compared with cognitively impaired residents (27%), and those with a diagnosis of dementia (12%).[22]

In a larger and more recent analysis, Reynolds et al reported similar results.[23] Data collected from 6 nursing homes, with a total of 551 residents, found that reports of pain decreased as cognitive abilities declined. While 80% of residents who were cognitively intact received pain medications, only 56% of those with severe impairments did (P<.001). Even though the diagnoses likely to cause pain were similar among all residents, those with severe cognitive impairments had fewer orders for scheduled pain medications.

Among older adults, physical accessibility to treatment, the cost of drug therapy, the presence of comorbidities, and the use of concomitant medication may represent barriers to effective pain management.[15] Sensory impairments, such as those affecting vision and hearing, memory difficulties, and lack of social backup, can all interfere with the diagnosis and treatment of pain. Vision problems, for example, can affect an individual’s ability to read the pharmacy labels for dose and frequency, and a patient living alone may be unable to obtain assistance with drug administration.

Provider Issues

Some data indicate that primary care practitioners in the community setting may feel that they have not been adequately prepared and trained to treat persistent pain and derive low satisfaction in delivering that care.[24] Gaps in knowledge and assessment skills, along with negative attitudes and hesitancy towards prescribing opioids, can also affect prescribing practices.

Even among clinicians experienced in pain management, there is some degree of controversy surrounding the use of opioids to treat persistent noncancer pain. In a survey of Canadian physicians with a defined interest in either palliative or noncancer care, Morley-Forster et al reported that for treating chronic pain related to cancer, an opioid was the treatment of choice for 79% of respondents.[25] But for moderate-to-severe chronic noncancer pain, opioids were the first-line treatment of only 32%.

While 63% of the surveyed physicians would use opioids as a second-line therapy, 23% of palliative care specialists and 35% of family practitioners reported that they would not use them to treat persistent noncancer pain even as a third-line treatment.[25] In addition, 68% felt that moderate-to-severe chronic pain was inadequately managed in Canada, and nearly 60% also thought that improvements in clinician education could enhance pain management.

Fear of regulatory actions regarding opioid prescribing, and reports of diversion and abuse have also affected the use of these agents.[17] A survey of California physicians reported that 40% of respondents limited their use of opioids for nonmalignant pain because they feared legal investigations.[25] Concerns about regulatory scrutiny can result in clinicians prescribing lower and potentially ineffective doses of opioids, or selecting less effective analgesics.[18]

Comprehensive Management Needed

Managing persistent pain in older adults often requires an interdisciplinary care approach, as the treatment plan may be complicated by the presence of comorbidities, polypharmacy, and possibly cognitive or sensory impairment.

Treatment goals in this population should not only be geared toward relieving pain, but should optimize functional goals, enhance activities of daily living, and improve overall quality of life. The heterogeneity of the older adult population, which can vary from healthy and robust to frail with limited mobility, requires an individualized approach to treatment. The primary cause of pain should be evaluated, diagnosed, and treated, if possible, prior to beginning analgesic therapy. The overall management approach must then be multifaceted. As the most common approach for managing persistent pain in this population is the use of pharmacologic agents, and because this modality requires the greatest care to avoid adverse events, the focus of this activity is on pharmacotherapy.

Combining pharmacologic and nonpharmacologic strategies, however, has been found to enhance the relief of pain for many patients.[2,26] Nondrug approaches include such modalities as exercise, cognitive-behavioral therapies, physical therapy, and acupuncture. One analysis of older adults found that acetaminophen (61%), regular exercise (58%), prayer (53%), and heat and cold (48%) were the most frequently used pain management strategies.[27] Although the number of randomized controlled trials of nonpharmacologic interventions in older adults is limited, there is sufficient evidence to support the use of selected nonpharmacologic approaches.[28] And, indeed, many older persons initiate complementary and alternative therapies.[29] Their use should be considered and incorporated into a comprehensive plan of pain care.

Challenges in the Assessment of Pain in Older Adults

Pain assessment in older adults must be comprehensive and multidimensional to develop a successful and individualized management plan. The goal is to identify the cause of pain, and a multidisciplinary approach may be needed,[8] as management can be complicated by multiple, concomitant causes and locations of pain. This can often make it difficult for the practitioner to differentiate acute pain caused by a new problem from that caused by an older chronic condition.

For various personal, cultural, or psychological reasons, older patients may not reveal that they are experiencing pain.[2] Therefore, it is essential that they are routinely screened and carefully assessed for the presence of pain. During the evaluation, an interdisciplinary assessment can help identify the source of potentially treatable pain. Referral to an appropriate specialist, such as a physical therapist, psychiatrist, or pain specialist, may be indicated.

Data suggest that there may be age-specific differences in the perception of and response to pain, and that advancing age comes with a higher threshold for pain.[15,16] Older persons respond less to mild pain, but may be more sensitive to severe pain. The higher threshold for pain can interfere with pain assessment, and lead to delayed treatment and recovery.

The reasons for this remain undefined, and may be related to structural, biochemical, and functional age-related changes in the peripheral nervous system, such as reduced density of myelinated and unmyelinated fibers and increasing neuronal damage and deterioration.[16] Age-related alterations also include a decline in the content and turnover of neurotransmitter systems connected with nociception. Similar changes have also been observed in the central nervous system (CNS).

Classifications of Pain

Pain is a subjective experience and difficult to measure objectively. Self-report tends to be the most accurate way to determine the existence and qualities of pain.[2]

Acute pain comes on quickly, can be severe, but is relatively short-lasting and subsides with healing. Chronic or persistent pain can range from mild to severe, and either persists after normal tissue healing (eg, postherpetic neuralgia), or is associated with an ongoing chronic condition such as osteoarthritis.[30]

The terms ‘‘persistent pain’’ and ‘‘chronic pain’’ are often used interchangeably in medical literature. Updated guidelines from the American Geriatrics Society (AGS) endorse “persistent pain” as the preferred terminology, as it is not associated with the negative attitudes and stereotypes often linked to the ‘‘chronic pain” label.[2]

Pain is further classified by its cause, and categorized as nociceptive, neuropathic, or of mixed etiology. Nociceptive pain refers to sensations that are caused by the stimulation of specific peripheral or visceral pain receptors, and among older adults, is often associated with trauma, inflammation, musculoskeletal disease, or ischemic disorders.[19,30] Neuropathic pain refers to pain caused by damage to the peripheral or CNS, and is commonly caused by nerve trauma, diabetic and other peripheral neuropathies, postherpetic and trigeminal neuralgias, stroke, and chemotherapy treatment.

Some common pain conditions, including myofascial pain, chronic back pain, and fibromyalgia, cannot be labeled as purely nociceptive or purely neuropathic, but rather contain elements of both.[19]

Persistent pain in older adults is most often associated with musculoskeletal disorders, including osteoarthritis, ankylosing spondylitis, and rheumatoid arthritis.[31] Approximately half of the adult population aged 75 years and older has reported experiencing joint pain.[32] Musculoskeletal disorders are reported by 72% of persons aged 75 years and older.[33]

Screening and Clinical Evaluation

Pain has been described as the “fifth vital sign,” and it is important to evaluate for pain when caring for older adults.[5-7] The Veterans Health Administration, as an example, has implemented “Pain as the 5th Vital Sign” in all inpatient and outpatient clinical settings to ensure consistent recognition and assessment of pain intensity and pain’s effects on function and quality of life.[34]

A comprehensive pain assessment should include a careful history and physical, a pain history, assessment of patient’s functional and psychosocial status, and diagnostic studies aimed at identifying the precise etiology of pain. Patients with cognitive impairments can be screened with the use of specific tools and simple questions. A review of the patient’s medical records may also be helpful during the initial assessment process.[21]

Present Pain Complaint and Medical History

The assessment of pain needs to include a detailed description of its onset, duration, frequency, intensity, location, and possible contributing factors. Questions relating to pain and how it affects normal daily activity, for example, or the use of analgesics, can be very helpful in assessing the intensity.[21] A pain map can assist in pinpointing the location of pain.

The patient’s medical history, including that of the current complaint, is the most important initial source of information about pain.[19] The history should include information about past medical, surgical, and psychiatric conditions, as well as any accidents or injuries. This data is important in identifying pre-existing conditions, and can greatly assist with treatment planning. In addition, the presence of comorbid conditions can influence pain perception and behavior.

Older adults frequently have multiple chronic health conditions and may be using several different classes of drugs.[19] The medication history must include not only all current and past prescribed medications, but also any over-the-counter pharmaceuticals, herbs, and nutritional supplements that the patient is using. Doses, side effects, and responses should be identified, along with tobacco, alcohol, and illicit drug use.[8,20]

Physical Examination

A physical examination complements the pain and medical history, and should include an evaluation of a patient’s general physical, neurologic, musculoskeletal, and cognitive status. Since musculoskeletal and neurologic conditions are the most common causes of persistent pain cited in this population, the examination should initially target those systems, but also be guided by the information procured during the history-taking.[19] Laboratory and imaging studies should corroborate physical examination findings to refine the differential diagnosis and treatment plan, depending on the older person’s health status and the likelihood that the findings will impact treatment decision. For example, if the person is not a candidate for surgery, imaging studies for spinal stenosis may not be necessary.

Functional Assessment

Clinicians need to include a comprehensive functional assessment, which evaluates cognitive, physical, and psychosocial aspects of the patient’s life.[21] The functional assessment is necessary to establish a baseline and gauge response to treatment. A patient’s self-reported measure of function should be considered as an adjunct to clinical evaluations/examinations, as the scope of the questions outlined by assessment tools varies and are generally not equally relevant to all patients or pain conditions.[19] While a variety of tools are available, those that are preferable have been developed and/or standardized in older adults, are time efficient, and do not place an excess burden on the patient.

An assessment of physical function should evaluate mobility, activities of daily living, sleep pattern, and appetite. The assessment should especially make note of the negative impact that pain has recently had on activities of daily living and pleasurable activities.

For physical functional assessment, the 2 most strongly recommended brief self-report tools are[19]

  • Functional Status Index (FSI)—which takes, on average, 8 minutes for the patient to complete and measures both basic and instrumental activities of daily living. The FSI Difficulty subscale (as opposed to the Pain subscale) is recommended to focus the patient’s attention on performing tasks, rather than the degree of pain experienced while doing so.
  • Human Activity Profile (HAP)—is used to measure current and previous activity levels, and is a particularly useful tool in older adults with persistent pain.

Another recommended tool is the Physical Performance Test (PPT), which measures both upper and lower body function.[19] In addition, the Gait Speed and/or the Short Physical Performance Battery are also recommended to measure general mobility performance. Some recommend focusing on tools that measure the impact of pain on physical and psychosocial functioning, such as the Brief Pain Inventory or the Geriatric Pain Measure. Both tools have been validated for use with older adults.

As many older patients suffer from cognitive impairment, either from an underlying pathology or medication, it is important to gauge a baseline for cognitive function. This would include assessing factors such as fluid reasoning, processing speed, and short-term memory, which may decline as part of the normal aging process. For patients with apparent cognitive impairments, conditions other than dementia should be considered as underlying causes.[8] The use of certain medications, depression, and poor nutritional status can all affect cognitive status, for example.

Both acute and persistent pain can affect cognitive status, and patient function can be ascertained by questioning the individual and family members/caregivers about associated problems such as aphasia or memory loss.[19] The Mini-Mental State Examination (MMSE) is widely used to screen for cognitive impairment in older adults, and requires 5 to 10 minutes to administer.[27] The test items assess orientation, memory, attention, and calculation, and the MMSE has been demonstrated to be valid, with good test-retest reliability. While this is a brief and standardized manner to gain an overview of cognitive status, Hadjistavropoulos et al caution that highly educated individuals with dementia may score within the reference range while those with a more limited educational status may well score in the range of dementia.[19] With this in mind, additional testing should be pursued for patients who score in a range that suggests dementia. Another tool that is brief to administer and clinically useful in screening for dementia is the Mini-Cog.[35]

For noncommunicative patients, or those with moderate-to-severe dementia, clinicians should attempt to assess pain by self-report if at all possible, direct observation for behaviors that may indicate the presence of pain, or from caregivers.[14] Another alternative is to administer analgesics and then evaluate if behavioral changes thought to be related to pain are altered.[20]

Psychosocial Assessment

Finally, a psychosocial assessment is needed to identify social support systems, financial resources, patient mood, and the presence of depressive symptoms or anxiety. All of these factors can affect and influence the perception of pain, as well as the response to treatment.[21] Depression is common in persons trying to cope with pain, and may also be comorbid with other emotional disorders such as anxiety.[19]

Instruments such as the Geriatric Depression Scale can be used to determine if further evaluation for depression is needed. With a focus on affective rather than physical symptoms, it has been found to be simpler for older adults to complete compared with other depression measure tools.[27] The Beck Anxiety Inventory, a short screening tool, can be utilized to evaluate for anxiety symptoms.

Pain Scales

Pain assessment tools can aid in measuring the intensity and severity of symptoms and the impact of pain on quality of life. Standardized assessment tools also promote consistency among practitioners and institutional settings.

The same tool should be used each time an assessment takes place, and also when the patient’s condition is re-evaluated after treatment is initiated. This is important as the various pain tools are not interchangeable with comparable findings. A variety of best practice tools and resources are available at the Geriatric Pain Web site for clinicians looking to improve pain assessment and management practices.

Pain diaries are also helpful in gathering information about pain and response to treatment, especially among community dwelling older adults.[19] A pain diary can be particularly useful for identifying triggers that may cause exacerbations of pain, as well as factors that decrease pain. However, lack of adherence and recall bias can limit the usefulness of pain diaries.

For adults with mild-to-moderate impairment, clinicians can attempt to use the Numeric Rating Scale, Verbal Descriptor Scale or Pain Thermometer, or the Faces Pain Scale. Among adults with more advanced impairment, an interdisciplinary expert consensus concluded that the Pain Assessment in Advanced Dementia (PAINAD) and the Pain Assessment Checklist for Seniors with Limited Ability to Communicate (PACSLAC) are the most clinically relevant tools available at this time, and most readily integrated into everyday practice.[21]

These tools were found to be particularly useful among nursing home residents, where the high prevalence and undertreatment of pain among individuals with severe impairment has been reported.[22,23] While the PAINAD is recommended for directly monitoring observable behaviors on a regular basis, the PACSLAC is recommended as a screening tool to monitor changes in behavior that might be related to pain.[37]

Pharmacologic Therapies

Choosing an analgesic treatment will largely depend on the cause and intensity of pain and other individual patient factors, such as the presence of comorbidities, drug-drug interactions, drug-disease interactions, adherence to therapy, and cost.

Even though older patients are generally at a heightened risk of adverse events, pharmacologic therapy can be safely initiated, and be effective, when all risk factors are taken into consideration.[2] Clinicians must assume, however, that there may be age-associated differences in the effectiveness and toxicity of the therapy, and that pharmacokinetic and pharmacodynamic drug properties will be altered in the older population.

Selecting Appropriate Medication and Dosing

Among older adults, the clinical manifestations of persistent pain are often complex and multifactorial, and comorbidities and other health issues make both evaluation and treatment more difficult.[2] In addition, older adults have a heightened potential for drug-related adverse events and a higher risk for complications.

The optimal treatment regimen is one that has a good probability of reducing pain and associated disability, and improving function and quality of life. However, guidelines from the AGS note that it is unrealistic for clinicians to imply, or for patients to expect, that pain will be completely eliminated in all cases.[2] Instead, the patient and practitioner need to establish mutual and realistic goals to manage pain, and reach a level of comfort that can improve quality of life.

Older adults use an average of 2 to 5 prescription medications on a regular basis.[38] It is estimated that polypharmacy, defined as the use of 5 or more medications, exists in 20% to 40% of the older population. Therefore, drug-disease and drug-drug interactions often have to be considered when selecting an analgesic therapy.

In addition, age-related alterations in drug absorption, distribution, metabolism, and excretion can result in greater variability in duration of action and plasma concentration for many analgesics; therefore, lower initial dosing and slower titration are recommended to optimize safety.[2,4]

Most analgesics do not have recommendations for age-adjusted dosing, and since older adults comprise a very heterogeneous group, it is difficult to predict common side effects or derive an optimum dose.[2] The dosing adage of “start low and go slow” is largely based on pharmacokinetic considerations and the desire to avoid adverse reactions, and not data from clinical trials.[5-7,38] But in the absence of dosage guidelines that can be generalized to a wide population, the initiation of therapy at a low dosage followed by careful upward titration, with frequent monitoring and follow-up, is advisable for older adults.

The least-invasive method of drug administration should also be used. For most patients, the oral route is the most convenient and provides relatively steady blood concentrations of the drug.[2] Other routes, such as intravenous, subcutaneous, and intramuscular, provide a more rapid onset but shorter duration than oral, and are also more invasive, require more technical skill, and are less convenient for the patient. Individuals with swallowing difficulties may benefit from transdermal, rectal, and oral transmucosal routes of administration.

Timing of medication administration is another important consideration. For example, rapid-onset, short-acting analgesics are required for severe episodic pain, while for continuous pain, medications should be provided around the clock.[2] Medication can also be prescribed on an “as needed” basis, but for cognitively impaired patients, who may be unable to request pain relief, scheduled administration is recommended.

The integration of one or more pharmacologic agents that have a synergistic effect may be more effective than monotherapy in managing a painful condition.[2] While monotherapy eliminates potential competing mechanisms of metabolism and drug-drug interactions, a single therapeutic agent may require dose escalation for adequate pain control. This increases the risk of adverse events, drug discontinuance, and switching agents. A multidrug approach may be more effective and efficient when 2 or more drugs with complementary mechanisms of action work synergistically to give greater relief with less toxicity. This strategy of ‘‘rational polypharmacy’’ may be an important intervention for some patients.

Available Agents: Pros and Cons in Older Patients

Pharmacotherapy for managing persistent pain can be divided into 3 categories: nonopioid, opioid, and adjuvant therapies.[2,5-7]

Nonopioid

<Acetaminophen. Acetaminophen is an effective analgesic, particularly for musculoskeletal pain, including osteoarthritis and low back pain. AGS guidelines recommend acetaminophen as initial and ongoing pharmacotherapy in the treatment of persistent pain.[2] Compared with traditional nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen is associated with less gastrointestinal (GI) and renal toxicity, fewer drug interactions, and importantly, no age-related differences in drug clearance.[4]

If pain relief is unsatisfactory, clinicians should consider raising the dose before prescribing a more potent agent.[2] However, very high doses can cause toxicity and patients and/or caregivers need to be educated about the maximum safe dose (currently, 4 g/24 hours) of acetaminophen from all sources. FDA advisors have urged that this maximum daily dose be lowered because of concerns that the drug can cause liver damage, even death, if used improperly.[39] Many patients may take more than the recommended dose because they are unaware of the potential risks of what they perceive as a “safe” drug. They may also be unaware that acetaminophen is found as an ingredient in numerous over-the-counter agents, including cold remedies, which may lead them to exceed the recommended maximum dose unintentionally.

Acetaminophen is less effective than NSAIDs in relieving inflammatory conditions, such as rheumatoid arthritis, and is contraindicated in patients with liver failure. It should be used cautiously, if at all, in patients with hepatic insufficiency and chronic alcohol abuse or dependence. For such patients, the maximum dose should be reduced 50% to 75%.[2]

NSAIDs. Nonselective NSAIDs are widely used to treat common musculoskeletal and inflammatory pain conditions, and in general, over-the-counter agents have a good safety profile. Particular caution must be exercised if used in patients with low creatinine clearance, gastropathy, cardiovascular disease, or intravascularly depleted states such as congestive heart failure.[2] While adverse drug reactions are a significant cause of morbidity and mortality among older adults, one study found that of older adults hospitalized for adverse drug reactions, nearly one-quarter (23.7%) were attributed to NSAID use.[31]

Compared with younger patients, those older than age 60 have a 3-fold risk of gastrointestinal complications.[4] The incidence of gastrointestinal toxicity induced by NSAIDs also appears to be more time- and dose-dependent, rather than associated with the specific drug utilized.[40] A meta-analysis found that the relative risks of GI adverse reactions in persons using NSAIDs, versus untreated controls, varied from 1.2 to 5.6.[40]

Several studies have found that combining NSAIDs with other drugs has led to an increase in serious reactions. The risk of hemorrhagic peptic ulcer disease jumps almost 13-fold when NSAIDs are used with the common anticoagulant warfarin.[4] Heerdink et al also found that the concomitant use of diuretics and NSAIDs was associated with a 2-fold increased risk of hospitalization for congestive heart failure in persons aged 55 years and older.[41] This was particularly pronounced for patients with existing serious congestive heart failure. In addition, the risk for GI bleeding is increased when NSAIDs are used concomitantly with low-dose aspirin, often administered as a cardioprotective agent.[2] These agents also may interfere with antihypertensive agents.[2]

Cyclooxygenase-2 (COX-2) selective inhibitors were introduced with the hope of reducing GI toxicity. While their use has been associated with fewer significant GI adverse events, the protection incurred is not complete. In addition, the other types of NSAID-related toxicities are the same.[2] Celecoxib is currently the only COX-2 inhibitor remaining on the market, as both rofecoxib and valdecoxib were withdrawn due to concerns about unacceptable risks of adverse cardiovascular events.

Topical NSAIDs, such as diclofenac or salicylate derivatives and compounded topicals, have also been introduced as an alternative to traditional oral agents. A number of studies support the efficacy and safety of these agents in relieving chronic painful musculoskeletal conditions,[42] but as insufficient numbers of older persons have participated in trials, the risks to this population are still unclear.[4] One agent, diclofenac sodium 1% gel, approved for the treatment of osteoarthritis pain, has demonstrated greatly reduced systemic levels compared with oral equivalent doses. There are no long term comparative studies for gastrointestinal or cardiovascular safety.

Overall, the AGS has issued the following recommendations for clinicians, when considering NSAID use in the older population[2]:

  • Both nonselective NSAIDs and COX-2 inhibitors may be considered on rare occasions and used with extreme caution in highly selected patients.
  • There should be an ongoing assessment of risks and complications, and these should be outweighed by therapeutic benefits.
  • A proton pump inhibitor or misoprostol for gastrointestinal protection should be used concurrently with nonselective NSAIDs.
  • Patients taking a COX-2 selective inhibitor concurrently with aspirin should also use a proton pump inhibitor or misoprostol.
  • Clinicians should routinely monitor all patients taking NSAIDs for gastrointestinal and renal toxicity, hypertension, heart failure, and other drug–drug and drug–disease interactions.
Opioids

Opioid analgesics are widely accepted for first-line treatment of severe acute pain and chronic pain related to cancer or at the end of life[30]; however, the use of opioids to treat noncancer pain remains controversial. Although there are diverse opinions on the subject, opioid analgesics can be an effective therapy for selected patients with persistent noncancer pain.[2,30]

No studies have evaluated the long-term efficacy and safety of opioids for noncancer pain in older adults. The American Pain Society (APS) and American Academy of Pain Medicine (AAPM) have recently issued joint guidelines regarding the use of opioids for persistent noncancer pain, but they address the entire adult population.[30]

The AGS includes the use of opioid analgesics in its updated guidelines on persistent pain in older adults.[2] In addition, a recent consensus statement from a multidisciplinary group of experts, which reviewed and evaluated the efficacy and tolerability of the 6 most commonly used World Health Organization step III opioids for older patients, also provides practical recommendations for use in this population.[16]

Long-term use of opioids for persistent pain may be associated with fewer potential life-threatening risks compared with long-term NSAID use, but opioids have their own set of potential risks.[4] They can cause constipation, nausea and vomiting, sedation, impaired cognition and psychomotor function, and respiratory depression.[16] While most adverse events do decline over time, extended use of opioids may suppress the production of several hypothalamic, pituitary, gonadal, and adrenal hormones.[2] Thus, long-term use requires careful monitoring for the development of adverse events.

Clinical trials have established the efficacy of numerous opioid agents in the treatment of persistent pain associated with musculoskeletal conditions, such as osteoarthritis and low back pain, along with painful neuropathic conditions such as diabetic peripheral neuropathy. However, long-term effectiveness in all age groups has not been clearly established.[2]

Opioid diversion and misuse and abuse can also become a concern, especially among patients with a history of substance-use disorder.[2,30] While the incidence of addictive behavior, and misuse and abuse are significantly lower in the older population, few long-term studies have been conducted.[2,4] Caution should be exercised when prescribing opioid therapy over several years; however, because given certain genetic and environmental factors, some patients are likely to abuse these drugs.

Opioids should be prescribed only with clearly defined therapeutic goals, after weighing the potential positive effects on pain and function against potential risks.[2,30] The selected agent should be provided on a trial basis initially, starting at a low dose and then titrated slowly.

An initial risk assessment, using tools such as the Opioid Risk Tool (ORT) or the revised version of the Screener and Opioid Assessment for Patients with Pain (SOAPP®), can assist the clinician to determine the presence of risk factors known to be associated with abuse/misuse of these agents.[2] Once opioids have been prescribed, the Current Opioid Misuse Measure, a self-assessment tool, can be used to identify patient misuse. A positive score on these screening tools does not indicate the person will abuse, but increases awareness of potential risk that requires ongoing monitoring and in some cases a treatment agreement.

Although vigilance regarding misuse or abuse of opioids is important in all patients irrespective of age, some experts suggest that underuse may be a larger problem among the elderly.[2] Many older patients may never fill their prescriptions or may use their opioid medication sparingly, due to concerns that include fears of addiction, the discomfort of associated constipation, social stigma, and cost. Therefore, it is important for clinicians to discuss these issues with their patients, and investigate their patients’ beliefs and prior experiences with this class of medications before beginning opioid therapy.[2]

AGS guidelines recommend that—

  • All patients with moderate-to-severe pain, pain-related functional impairment, or diminished quality of life due to pain should be considered for opioid therapy.
  • Potential adverse effects should be anticipated, assessed for, and identified.
  • Maximal safe doses of acetaminophen or NSAIDs should not be exceeded when used in combination with a fixed-dose opioid.
  • Breakthrough pain should be anticipated, assessed, and prevented or treated when using long-acting opioids.
  • Therapeutic goals should be reassessed, and patients monitored for adverse effects, and safe and responsible medication use.
Adjuvant Analgesic Drugs

Adjuvant drugs can be used alone or in combination with an opioid or a nonopioid analgesic to treat persistent pain conditions. Some of these agents are indicated for specific pain problems, such as neuropathic pain and fibromyalgia. Others are not specifically developed or indicated for pain relief nor classically categorized as analgesics but found to be effective in attenuating certain pain syndromes. For instance, clinical trials of certain adjuvant analgesics in the treatment of chronic low back pain are promising.

Drug classes that fall into this category include antidepressants, anticonvulsants, corticosteroids, muscle relaxants, benzodiazepines. and topical analgesics.

Translating Science Into Best Practices

Effective treatment begins with a comprehensive assessment, and all older adults should be screened for persistent pain in all types of healthcare settings.[19] If pain is identified, then a comprehensive evaluation should be conducted that includes pain history, medical history, complete physical examination, and a functional assessment.

Older adults with persistent pain that causes functional impairment and/or adversely affects quality of life are candidates for pharmacologic therapy. The type of therapy selected will largely depend on the intensity and cause of pain, and individual patient’s characteristics. Response to therapy should be reassessed periodically, with interventions revised if pain is not being adequately controlled. Likewise, if the pain is resolved, medication can sometimes be tapered, switched, or stopped completely.

A number of guidelines are now available to help healthcare professionals in the assessment and particularly the treatment of persistent pain in older adults. AGS guidelines urge caution in the use of NSAIDs, and recommend the least invasive route for giving medication.[2] The AGS, along with other professional organizations, affirms that opioids are effective for relieving moderate-to-severe pain and are associated with a low potential for addiction in patients who do not have a history of abuse or addiction. In older persons with persistent pain, opioids are associated with fewer long-term risks than other drug regimens, such as NSAIDs.

Pharmacotherapy is usually needed, particularly when pain interferes with physical and psychological function and quality of life. However, nonpharmacologic therapies, including exercise, massage, physical therapy, biofeedback, cognitive-behavioral therapy, acupuncture, and transcutaneous electrical nerve stimulation, can optimize and enhance the effects of drug therapy.[2,5-7] Interventional techniques, such as joint and muscle injections of local anesthetics or steroids, can also play an important role in managing selected chronic pain conditions. Referral to specialists may be necessary for diagnosis and treatment of complex conditions.

Due to the often complex nature of their healthcare needs, older patients require the coordinated and comprehensive services that can be offered through a patient-centered primary care medical home.[43] In the medical home model, the primary care clinician provides most of the patient’s healthcare needs, taking responsibility for appropriately arranging care with other qualified professionals[43] as needed. Patient care is coordinated and/or integrated across all elements of the healthcare system, both in institutional and community settings.

Persistent pain in the older population generally requires a multidisciplinary approach in formulating a pain management plan that is appropriate and effective for the individual patient.

 

Bruce A. Ferrell, MD; Perry G. Fine, MD; Keela A. Herr, PhD, RN, AGSF, FAAN
Published on September 21, 2010

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