CGRP Inhibitors Should Not Be Used for Complex Regional Pain Syndrome
CGRP inhibitors such as erenumab have no role in treating CRPS and should not be used—these medications are FDA-approved and guideline-recommended exclusively for migraine prevention, not for neuropathic pain syndromes. 1
Why CGRP Inhibitors Are Not Appropriate for CRPS
- No evidence exists supporting CGRP inhibitor use in CRPS, and established guideline-based treatments with proven efficacy should be used instead 1
- CGRP inhibitors (erenumab, fremanezumab, galcanezumab, eptinezumab) are specifically indicated only for episodic and chronic migraine prevention 2
- The mechanism of action—blocking CGRP receptors to prevent migraine attacks—does not address the complex pathophysiology of CRPS, which involves inflammatory, neuropathic, and sympathetically-mediated pain components 3
Evidence-Based Treatment Algorithm for CRPS
Immediate Initiation (All Patients, <3 Months)
- Start physical therapy immediately with gentle stretching and active range of motion exercises—this is the cornerstone of CRPS management regardless of other interventions 1, 4, 5
- Initiate acetaminophen or ibuprofen (if no contraindications) for pain control to enable participation in physical therapy 1, 4
- Consider short-course oral corticosteroids (30-50 mg daily for 3-5 days, then taper over 1-2 weeks) to reduce swelling and pain in early CRPS 1, 4, 6, 7
Persistent CRPS (3-6 Months)
- Continue physical therapy as the foundation of treatment 5
- Consider sympathetic blocks (stellate ganglion or lumbar sympathetic blocks) when there is consistent improvement and increasing duration of pain relief with each successive block 1, 4
- These blocks should only be used as components of multimodal treatment, not as monotherapy 4
- Intranasal or intramuscular calcitonin may provide benefit despite some contradictory evidence 6, 7
- Intravenous bisphosphonates show clear benefits and should be considered 6, 8
Refractory CRPS (>6 Months)
- Spinal cord stimulation should be considered after failure of conservative therapies, with a trial performed before permanent implantation 1, 4, 6
- Implement TENS as part of a multimodal approach to pain management 1, 4
- Consider gabapentin for neuropathic pain component 7, 8
- Botulinum toxin injections into affected muscles when pain is related to spasticity 4
Critical Pitfalls to Avoid
- Never delay physical therapy waiting for pain to resolve—this worsens outcomes through disuse and pain upregulation 5
- Do not use CGRP inhibitors or other unproven therapies when evidence-based options exist 1
- Avoid continuing sympathetic blocks indefinitely without documented progressive improvement and increasing duration of relief 4
- Do not use sympathetic blocks for non-CRPS neuropathic pain—this contradicts evidence-based guidelines 4
- Avoid sympathectomy, which has a high likelihood of adverse outcomes without proven efficacy 6
- Do not use peripheral somatic nerve blocks for long-term treatment of chronic pain 4
Monitoring Requirements
- Document objective functional outcomes beyond pain scores, including activities of daily living, cognitive function, autonomic stability, and temperature dysregulation 4
- Evaluate patients at least twice annually by a specialist due to high recurrence risk 5
- For sympathetic blocks, record duration of relief with each successive block to demonstrate the required pattern of "increasing duration" 4