As the population ages, spine-related pain is increasingly common in older adults. While medications play an important role in pain management, their use has limitations in geriatric patients due to reduced liver and renal function, comorbid medical problems, and polypharmacy. This review will assess the evidence basis for medications used for spine-related pain in older adults, with a focus on drug metabolism and adverse drug reactions. A PubMed/OVID search crossing common spine, neck, and back pain terms with key words for older adults and geriatrics was combined with common drug classes and common drug names and limited to clinical trials and age over 65 years. The results were then reviewed with identification of commonly used drugs and drug categories: nonsteroidal anti-inflammatories (NSAIDs), acetaminophen, corticosteroids, gabapentin and pregabalin, antispastic and antispasmodic muscle relaxants, tricyclic antidepressants (TCAs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tramadol, and opioids. Collectively, 138 double-blind, placebo-controlled trials were the focus of the review. The review found a variable contribution of high-quality studies examining the efficacy of medications for spine pain primarily in the geriatric population. There was strong evidence for NSAID use with adjustments for gastrointestinal and renal risk factors. Gabapentin and pregabalin had mixed evidence for neuropathic pain. SNRIs had good evidence for neuropathic pain and a more favorable safety profile than TCAs. Tramadol had some evidence in older patients, but more so in persons aged < 65 years. Rational therapeutic choices based on geriatric spine pain diagnosis are helpful, such as NSAIDs and acetaminophen for arthritic and myofascial-based pain, gabapentinoids or duloxetine for neuropathic and radicular pain, antispastic agents for myofascial-based pain, and combination therapy for mixed etiologies. Tramadol can be well tolerated in older patients, but has risks of cognitive and classic opioid side effects. Otherwise, opioids are typically avoided in the treatment of spine-related pain in older adults due to their morbidity and mortality risk and are reserved for refractory severe pain. Whenever possible, beneficial geriatric spine pain pharmacotherapy should employ the lowest therapeutic doses with consideration of polypharmacy, potentially decreased renal and hepatic metabolism, and co-morbid medical disorders.
Acetaminophen (paracetamol) is safe in older adults, but non-steroidal anti-inflammatories (e.g. ibuprofen) may be more effective for spine-related pain. Non-steroidal anti-inflammatories should be used in short-term lower dose courses with gastrointestinal precaution. Corticosteroids have the least evidence for treating nonspecific back pain. Gabapentin and pregabalin may cause dizziness or difficulty walking, but may have some benefit for neck and back nerve pain (e.g. sciatica) in older adults. They should be used in lower doses with smaller dose adjustments. Some muscle relaxants (carisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, and orphenadrine) are avoided in older adults due to risk for sedation and falls. Others (tizanidine, baclofen, dantrolene) may be helpful for neck and back pain, with the most evidence for tizanidine and baclofen. These should be used in reduced doses, avoiding tizanidine with liver disease and reducing baclofen dosing with kidney disease. Older antidepressants are typically avoided in older adults due to their side effects, but nortriptyline and desipramine may be better tolerated for neck and back nerve pain at lower doses. Overall, newer antidepressants (namely duloxetine) have a better safety profile and good efficacy for spine-related nerve pain. Tramadol may be tolerated in older adults, but has risk for sedation, upset stomach, and constipation. It may be used in lower doses after alternative medications have failed, and works well with co-administered acetaminophen. Opioids are avoided due to their side effects and mortality risk, but low-dose opioid therapy may be helpful for severe refractory pain with close monitoring of patients clinically.
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