Day # 125: Treatment of Chronic Pain and Fibromyalgia

Today we will continue our current theme of psychosomatic disorders as we discuss the treatment of chronic pain syndromes (specifically non-cancer pain) and fibromyalgia.

Before you read this post make sure you read Day #124 which provides a detailed overview of chronic pain and fibromyalgia including definitions, examples of pain syndromes, epidemiology, pathogenesis, clinical pearls, and tips on the assessment and diagnosis.

Today's Content Level: Intermediate

NON-PHARMACOLOGIC TREATMENT 1, 2

• The overarching approach to treatment and pain management should reflect the biopsychosocial nature of chronic pain. Typically, a multidimensional treatment strategy is most effective.

• Education and Psychotherapy: patient education is a crucial component for goals, expectation management, and reducing normal fears regarding pain.

• Cognitive-behavioral therapy for chronic pain (CBT-CP) has evidence that suggest improvement in functioning and quality of life for a variety of chronic pain conditions and can be delivered alone or as a component of an integrated multimodal pain management program. Acceptance and commitment therapy (ACT) has also been studied. Somatic therapies such as mindfulness based stress reduction (MBSR) therapy, relaxation therapy, and biofeedback have been used and shown to be effective, particularly MBSR. Sleep disturbance is very common in patients with chronic pain, thus treating with sleep hygiene or CBT for insomnia (CBT-i) may be warranted.

• Exercise / Physical Therapy: Initiating a low-level exercise program with gradual step-wise increases can improve pain, counteract reconditioning, and overcome fear/avoidance beliefs regarding their pain and performance. Activities include aerobic exercise, aquatic exercise, stretching programs, yoga, tai chi, qigong, or strength training. Individualized physical or occupational therapy programs may be indicated in some patients with chronic pain and functional limitations, particularly when severely deactivated.

• Physical and Procedural Interventions: depending on source/mechanism of pain options may include (from least to most invasive) massage, heat/cold therapy, ultrasound, transcutaneous electrical nerve stimulation (TENS), acupuncture, osteopathic or chiropractic manipulation, injections (trigger point, botox, facet blocks, hyaluronic acid, corticosteroids), radiofrequency ablation, intrathecal pumps, or deep brain stimulation.

PHARMACOTHERAPY 3, 4, 5

• General approach: The priority should be treating the underlying condition, if present. For patients with inadequate control of pain despite nonpharmacologic therapies, then augmentation with medications should be considered and carefully selected based on the type of pain (nociceptive, neuropathic, central sensitization, or a combination). NSAIDs are the mainstay of treatment of MSK pain and initial treatment for chronic neuropathic pain generally involves either selected antidepressants (TCAs or SNRIs) or anti-epileptics (gabapentin or pregabalin) with adjunctive topical therapies. Goals should be to improve function and quality of life and not just improvement of pain.

• NSAIDs and Acetaminophen: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the mainstay treatment of musculoskeletal (MSK) pain if pharmacotherapy is required. The efficacy of NSAIDs for chronic MSK pain without evidence of ongoing inflammation, such as low back pain, is low. Long-term chronic use may lead to stomach ulcers, renal failure, and increased bleeding risk. NSAIDs are not generally helpful in fibromyalgia. Acetaminophen is commonly used, however the evidence of efficacy for chronic pain is very limited and only a small subset of patients receive sustained meaningful reduction in pain.

• Topical agents: Topical agents have several potential advantages over oral medications for the treatment of well-localized pain such as fewer systemic side effects (lower rates of systemic absorption) and delivery at the specific site of pain. Options include topical NSAIDs (MSK pain), lidocaine (neuropathic pain), and capsaicin (MSK and neuropathic).

• Antidepressants: Tricyclic antidepressants (TCAs) and Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) are effective in neuropathic pain, fibromyalgia, migraines, other central sensitization syndromes, and even has some evidence for chronic low back pain and osteoarthritis. TCAs-> Amitriptyline has been the most widely studied TCA in chronic pain but others have also been used effectively including doxepin, nortriptyline, imipramine, and despiramine. It also improves sleep disturbances in patients with chronic pain. SNRIs-> Duloxetine has the largest evidence base of the antidepressants to support analgesic efficacy. Venlafaxine, at higher doses, also has some evidence for neuropathic pain. Milnacipran is FDA approved for the treatment of fibromyalgia and has been shown to improve pain and fatigue in these patients.

• Antiepileptics (AEDs): Gabapentin and pregabalin have proven efficacy verses placebo in several neuropathic pain conditions. Have also shown improvement in pain and sleep in fibromyalgia and pregabalin is commonly used first-line in this condition. Carbamazepine or oxcarbazepine is the first-line therapy for trigeminal neuralgia. Other AEDs have been used anecdotally and in randomized trials with limited evidence and should be reserved for specialty care third line treatments. These include topiramate, lamotrigine, levetiracetam, valproate, zonisamide, tiagabine, and the benzodiazepine clonazepam.

• Opioids: The use of opioids for chronic pain are associated with significant adverse events including falls, dependence, abuse, and overdose. The efficacy of opioids for neuropathic pain is uncertain and ineffective in fibromyalgia. Should be considered in those with high severity intractable pain or cancer-related pain.

• Marijuana and CBD: The use of cannabis and cannabinoids for chronic pain is controversial, and is complicated by the varied legal status throughout the US and the world. Systematic reviews and meta-analyses have reported mixed results on efficacy for chronic pain in general, but some support for the use of neuropathic pain.

• Antispasmodics: Agents include methocarbamol, metaxalone, carisoprodol, baclofen, and tizanidine. Muscle relaxants are commonly prescribed, however their use and mechanism are controversial. Many experts recommend avoiding the use of these medications due to limited evidence except for conditions associated with severe muscular spasticity (multiple sclerosis, cerebral palsy, spinal cord injury). Pain relief is likely related to CNS effects such as sedation rather than analgesic effects.

CONCLUSION

• Next lesson we will discuss chronic fatigue syndrome. If you want more learning resources then check out our recommended resources page.

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• Resources for today's post include: Pocket Psychiatry and Kaplan and Sadock Synposis of Psychiatry and the articles referenced in the text.