Case study 3 A 64-year-old female presents with severe pain in both anterior-lateral thighs and lateral shoulders, rated at 7/10 on the VAS. She reports that the pain is constant and that she gets only mild relief from NSAIDs. She cannot walk without a cane or walker. She had been diagnosed six years ago with severe peripheral neuropathy in her legs for which she was prescribed gababentin. She reports that gababentin gives her intense “brain fog” and forgetfulness, however, and that she has stopped taking it because of these side effects. The patient also has type 2 diabetes, initially treated with metformin but lately also with 50 units of insulin per day. The patient was given a treatment plan that included chiropractic adjustments and exercise rehabilitation exercises. She also adopted a “Paleo” diet, which she followed strictly for three months, although it did not significantly lower her hemoglobin A1c levels. She has come to you because the pain is eroding her quality of life, interrupting her sleep, and contributing to tensions with her partner. Questions: 1. Given the subjective nature of pain, how can a clinician more objectively assess the kind of pain reported by patients such as this? _____________________________________________________________________________________________ 2. Is it reasonable to believe that the gabapentin was responsible for her reported side effects? _______________________________________________________________________________________________ 3. Would Hannah be a good candidate for an opioid analgesic? Why or why not? _______________________________________________________________________________________________ 4. What non-pharmacological treatments might be tried for reducing this patient’s pain? _______________________________________________________________________________________________ Non-opioid pharmacologic treatments for acute pain Acetaminophen and NSAIDs
The FDA currently sets a maximum limit of 325 mg of acetaminophen in prescription combination products (e.g., hydrocodone and acetaminophen) in an attempt to limit liver damage and other potential ill effects of these products. 32 Topical agents Topical capsaicin and salicylates can both be effective for short term cutaneous pain relief and generally have fewer side effects than oral analgesics, but their long- term efficacy is not well studied. 111,,112 Topical aspirin, for example, can help reduce pain from acute herpes zoster infection. 107 Topical NSAIDs and lidocaine may also be effective for short-term relief of superficial pain with minimal side effects. Topical agents can be simple and effective for reducing pain associated with wound dressing changes, debridement of leg ulcers, and other sources of superficial pain. 103 Anticonvulsants Anticonvulsants, such as gabapentin, pregabalin, oxcarbazepine, and carbamazepine, are often prescribed for chronic neuropathic pain (e.g., post- herpetic neuralgia and diabetic neuropathy) although evidence for efficacy in acute pain conditions is weak. 114 A 2017 trial, for example, randomized 209 patients with sciatica pain to pregabalin 150 mg/day titrated to a maximum of 600 mg/day vs. placebo for 8 weeks. 115 At 8 weeks there was no significant difference in pain between groups (mean leg pain intensity on a 0-10 scale 3.7 with pregabalin vs. 3.1 with placebo, P=0.19).
In general, mild-to-moderate acute pain responds well to oral non-opioids (e.g., acetaminophen, NSAIDs, and topical agents). Although they are weaker analgesics than opioids, acetaminophen and NSAIDs do not produce tolerance, physical dependence, or addiction and they do not induce respiratory depression or constipation. Acetaminophen and NSAIDs are often added to an opioid regimen for their opioid-sparing effect. Since non-opioids relieve pain via different mechanisms than opioids, combination therapy can provide improved relief with fewer side effects. The choice of medication may be driven by patient risk factors for drug-related adverse effects (e.g., NSAIDs increase the rate of gastrointestinal, renal, and cardiovascular events). If acetaminophen or NSAIDs are contraindicated or have not sufficiently eased the patient’s pain or improved function despite maximal or combination therapy, other drug classes (e.g., opioids) are sometimes used. Non-opioid analgesics are not without risk, particularly in older patients. Potential adverse effects of NSAIDs include gastrointestinal problems (e.g., stomach upset, ulcers, perforation, bleeding, liver dysfunction), bleeding (i.e., antiplatelet effects), kidney dysfunction, hypersensitivity reactions, and cardiovascular concerns, particularly in the elderly. 109 The threshold dose for acetaminophen liver toxicity has not been established; however, the Food and Drug Administration (FDA) recommends that the total adult daily dose not exceed 4,000 mg in patients without liver disease (with a lower ceiling for older adults with certain conditions). 110
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