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By Adam J. Carinci, M.D.
 Introduction
Pain is the most common symptom for which older adults, typically defined as people aged 65 and older, seek medical treatment. The prevalence of persistent pain ranges from 24% to 50% in older adults, and generally increases with increasing age.1 Older adults are set to overwhelm the healthcare system. According to the latest United States Census Study, at present, approximately 13% of the population is 65 years and older. By the year 2050, approximately 20.6% of the population will be 65 years and older. Additionally, the oldest old, those 85+, presently account for just two percent of the population, and are projected to account for five percent by 2050. Understanding the challenges and unique needs of older adults with pain will be tantamount to delivering effective healthcare in the years ahead.
Common Sources of Pain in the Elderly
The most common sources of pain in the elderly involve one or more of the following: osteoarthritis, neuropathy, low back pain, and malignancy. Additionally, the sources of pain can be broken down into two major classifications: nociceptive pain and neuropathic pain.
Nociceptive pain involves pain derived from direct stimulation of pain receptors from either visceral (organs) or somatic (bones, muscles, skin) sources. Examples include myofascial pain, inflammatory disorders, and traumatic injuries. Such pain is usually aching or throbbing in quality, and is well localized. Nociceptive pain is part of normal pain processing and typically responds well to traditional analgesics, such as acetaminophen, NSAIDS, and opioids.
Neuropathic pain, in contrast, involves abnormal processing of sensory input by the peripheral or central nervous system, and entails pathologic changes in the nervous system itself. Painful disorders such as complex regional pain syndrome, post-herpetic neuralgia, phantom limb pain, and post-stroke pain are examples. Neuropathic pain is poorly localized and associated with burning, stinging, and electrical type sensations. It often responds to nontraditional analgesics such as antidepressants, anticonvulsants, and occasionally, opioids.
Barriers to Effective Pain Management
Pain is often unrecognized and undertreated in older adults.2 Further, the under-treatment of pain is associated with depression/anxiety, sleep disturbances, decreased physical functioning, social isolation, and worsening of other comorbid health problems. The reasons for this under-treatment are varied but can be roughly divided into patient-specific factors and physician-specific factors.
Patient-specific factors include:
• Expectation that pain is part of aging
• Fear of additional testing
• Perception of being a burden or troublesome patient
• Communication barriers (i.e., dementia)
Physician-specific factors include such variables as:
• Concern for adverse drug effects
• Concern for toxicity and/or polypharmacy
• Fear of addiction, in the case of opioids
Medicine and the Elderly
Older adults have multiple age-related changes that increase the risk of pharmacologic treatment of pain. Age-related changes in pharmacokinetics (what the body does to the drug) and pharmacodynamics (what the drug does to the body) lead to differences in drug absorption, distribution, and elimination. For example, kidney or liver disease will often lead to a prolonged duration of effect of many drugs that are metabolized by either of these organs. Therefore, a smaller initial dose, or a less frequent dosing regimen, is necessary to avoid overdosage and toxicity from the medication. In other cases, side effects from the medications themselves limit their applicability. NSAIDS, for example, can lead to gastrointestinal bleeding in susceptible patients; therefore, this side effect would limit its effectiveness. Lastly, older adults are more susceptible to adverse drug reactions from drug-drug interactions and polypharmacy as a result of the greater number of medications taken with increasing age. Many drugs are metabolized by the same enzymes in the body. When multiple medications are competing for breakdown by the same enzyme, delayed metabolism of one or both drugs may occur. Additionally, one medication may actually slow down or inhibit the enzyme required for the metabolism of another medication, thus prolonging its effect. While in other circumstances, it may speed up or stimulate the enzyme and actually hasten the metabolism of another medication thereby limiting its duration of effect.
Balancing the risks and benefits of treatment is an important aspect of pain medicine in older adults. On one hand, there are very real risks involved in instituting pain medications in older adults. Concerns of toxicity, sedation, and drug-drug interactions are well documented both anecdotally and in the medical literature. On the other hand, well managed pain can lead to greater degrees of functionality, cognitive improvement, increased self-worth, and happiness in older adults. A prudent and cautious approach is therefore warranted. Side effects can be anticipated, prevented, and managed.
When instituting opioids or other potent medications, the mantra of “start low and go slow” is essential. Judicious patient follow-up, communication, and symptom management is indispensable in catching problems early and steering clear of potentially life-threatening adverse drug reactions. Patient selection is crucial in the sense that one must match each patient to the appropriate medication taking into account that patient’s unique needs, comorbidities, and individual complexities. Lastly, referral to a pain medicine specialist is an important component of pain management in older adults with complex pain syndromes.
As the population continues to age, healthcare providers and others must accept that pain is not a normal part of aging. Older adults deserve the same standard of pain control that one would set for their younger counterparts. A thorough risk-benefit analysis coupled with an appropriate understanding of each patient’s unique needs and a respect for the physiologic changes associated with aging will allow for optimal pain control and patient satisfaction.
References:
1. Calvalien TA, Pain management in the elderly. J. Am. Osteopath Assoc. 2002:102(9):481-485.
2. Management of persistent pain in older persons. J. Am. Geriatr. Soc. 2002:50(6):s205-224.
About the Author: Dr. Carinci is a MPH candidate in Health Policy and Management at the Bloomberg School of Public Health at Johns Hopkins University. He currently practices in Hopkins Hospital’s Department of Anesthesiology and Critical Care Medicine.
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