Chronic Pain Management: An Evidence-Based Approach

Jennifer Reidy, MD, MS, FAAHPM

TREATMENT

• Goals of treatment are restoring function and a decrease in pain while balancing risks and benefits of therapies.
• Intradisciplinary teams offer most effective approach to chronic pain, including its physical, emotional, and psychological aspects. These teams may include the patient, family, primary care doctor, nurse, pain management specialist, pharmacist, psychologist, psychiatrist, physical and occupational therapists, physiatrist, complementary medicine practitioners, social worker, and (if needed) addiction medicine specialist (3)[B].
• Treatment should always include nonpharmacologic therapies such as exercise, cognitive-behavioral therapy (CBT), patient and family education, yoga, massage, relaxation techniques, support groups, meditation, and acupuncture.

GENERAL MEASURES
Keep a pain and function diary to record pain and activity level and how much medication is taken.

MEDICATION

• Always begin with exercise, physical therapy, CBT, and self-management skills before or with pain medications. Use sequential time-limited trials of medications, starting at low doses, and gradually increasing until either effect or dose-limiting side effects are reached. Rational polypharmacy may be indicated (such as an opioid + neuropathic agent).
• For mild to moderate chronic pain
  • Acetaminophen: daily dose not to exceed total 4 g in healthy adults and 2 g in the elderly or those with hepatic disease or active or past history of alcohol use
  • NSAIDs: COX-2 selective inhibitors should be used with caution because of cardiac risks but may have less gastric risk. If high cardiac risk consider nonselective COX inhibitor (such as naproxen) with or without gastric prophylaxis (depending on ulcer risk).
  • “Weak” opioids, including tramadol. Caution: Opioid analgesic combinations can lead to serious acetaminophen or NSAID toxicities if patients exceed safely prescribed doses.
  • Topical agents: NSAIDs, lidocaine (gel is less expensive than patch), ketamine, capsaicin
• For neuropathic pain
  • Classes of medications include (i) tricyclic antidepressants (desipramine and nortriptyline have fewer side effects); (ii) serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressants (duloxetine); (iii) anticonvulsants (alpha 2-delta ligands, gabapentin, and pregabalin); (iv) opioids, including tramadol. Example: combination of nortriptyline + gabapentin.
• For moderate to severe chronic pain
  • Strong opioids, including morphine, oxycodone, hydromorphone, oxymorphone, fentanyl. Check opioid equianalgesic tables for dosing by route of administration.
  • No evidence supports any of these strong opioids as superior or having improved side effect profile.
  • In patients with chronic back pain, opioids may be efficacious for short-term use, but long-term benefits and side effects are unclear; in addition, aberrant medication-taking behaviors range from 5% to 24%.
• Morphine should be avoided in patients with significant renal insufficiency.
• Methadone should only be prescribed by experienced providers. The only opioid that also acts as N-methyl-d-aspartate receptor antagonist, methadone has many drug interactions and can contribute to potentially fatal cardiac arrhythmias.
• Once stable dose of opioids is established, change to sustained-release formulations if pain is constant or very frequent. Short-acting formulations are only for breakthrough or episodic pain.
• Common side effects: constipation: Senna should be prescribed at time opioids are started; also nausea, sedation, mental status changes, and pruritus

Alert
Patients on chronic opioid therapy must agree to monitoring. Clinicians should use universal precautions and systems-based practice, including written agreements, random urine drug screens, pill/patch counts, and other measures (see “Ongoing Care”) (4,5)[B].

SURGERY/OTHER PROCEDURES
Consider interventional procedures, including joint injections, nerve blocks, spinal cord stimulation, and intrathecal medication among others, as needed.

COMPLEMENTARY & ALTERNATIVE THERAPIES

• Acupuncture: efficacy in chronic neck and back pain and fibromyalgia
• Exercise: efficacy in low back pain and fibromyalgia
• Improved mood and coping skills, decreased disability with CBT
• Mind–body interventions: yoga, tai chi, hypnosis, progressive muscle relaxation, meditation