Pain is common among older adults (defined as ≥65 years of age) whether from age-related arthritis or a serious illness.
Physiological changes with aging
• Studies suggest they may have an increased pain threshold, but a decreased pain tolerance compared to their younger counterparts. This means that they are less likely to label a sensation as “painful”, but when painful sensations occur, they can have more powerful negative effects such as depression, insomnia, agitation, or a change in mental status. They commonly have concurrent pain from multiple sites as they often have more comorbidities.
• With aging, there is decline in hepatic blood flow, GI motility, lean body mass, hepatic enzyme activity, and renal function. These changes lead to many medications having longer effects at lower doses and therefore a significantly higher risk for adverse effects.
These include cognitive-behavioral therapy, weight loss, exercise, occupational and physical therapy, and the use of assistive devices. These interventions may be directed more toward improving function, independent of analgesia.
Topical and local agents
Topical agents can be used for localized pain complaints, such as muscle or joint pain from injuries or arthritis. These include analgesic balms, lidocaine cream, capsaicin cream, and topical non-steroidal anti-inflammatory drugs (NSAIDs). Many older patients have contraindications to systemic NSAIDs, but topical NSAIDs can be prescribed to those with renal dysfunction or those at risk of other NSAID-induced adverse effects - when applied topically, diclofenac serum concentrations are 158 times less than with oral administration, and for knee osteoarthritis topical and oral diclofenac similarly effective.
Oral non-opioid analgesics
Acetaminophen (APAP) and NSAIDs can be used for nociceptive pain. In the management of chronic low back pain and osteoarthritis, oral APAP it is often used as first-line therapy due to its safety profile - scheduling it can improve adherence and analgesia, as opposed to instructing the patient to take it as needed. When APAP does not provide adequate analgesia, oral NSAIDs can be added but are limited by contraindications common in many patients (chronic kidney disease, history of GI bleeding, concurrent use of systemic-anticoagulation). Non-acetylated salicylates are preferred as they have a superior safety profile. If they fail, traditional NSAIDs can be considered for brief periods of time (<7 days), as often the risks associated with longer duration of use outweigh benefits.
Older adults also frequently suffer from neuropathic pain in the setting of post-herpetic neuralgia, post-stroke pain, or peripheral neuropathy. If a topical agent such as lidocaine is not found to be effective, gabapentin, pregabalin and antidepressants should be considered. Tricyclic antidepressants (TCAs) are considered some of the most effective adjuvant analgesics for neuropathic pain, however they are often intolerable to the older adult due to anticholinergic side effects (including delirium and falls). Nortriptyline or desipramine, secondary amines, may be more tolerable than amitriptyline, but are not free of these side effects. Therefore, selective norepinephrine and serotonin reuptake inhibitors (SNRIs) such as venlafaxine or duloxetine are thought to be more interesting options. Doses of venlafaxine, duloxetine, gabapentin and pregabalin should be considered for patients with renal dysfunction; doses of duloxetine should also be decreased in liver dysfunction.
A rational approach to prescribing for older patients includes considering non-drug and topical agents for nearly every patient due to their excellent safety profile. Non-opioid analgesics should be considered for all patients with pain that limits function (mobility, sleep, etc.), and adjuvant analgesics for patients with neuropathic pain syndromes.
See reference for more information.
Adapted from Pruskowski J, Wright R, Bhatbagar M. Pain management considerations in older adults. Palliative Care Network of Wisconsin. Fast facts and concepts #356. Internet. Accessed on January 6, 2019.