Management of Acute Musculoskeletal Injuries

Introduction to Capsaicin and Its Limitations

Capsaicin has established efficacy only for chronic neuropathic pain and chronic osteoarthritis, not acute injuries, as supported by the American College of Rheumatology 1, 2, 3, 4, 5, 6.
The mechanism of action of capsaicin, depleting substance P and desensitizing TRPV1 receptors, is designed for chronic pain conditions, requiring 2 to 4 weeks of continuous use before therapeutic effects are experienced, as noted by the Mayo Clinic 5.

Evidence-based concentrations of capsaicin are either 0.075% applied 3-4 times daily for 6-8 weeks for chronic conditions, or the 8% patch applied once under medical supervision for neuropathic pain, according to guidelines from the American Academy of Pain Medicine 5, 7, 8.

Topical NSAIDs, such as diclofenac gel, are the appropriate first-line topical treatment for acute soft tissue injuries like sprains, providing immediate anti-inflammatory and analgesic effects, as recommended by the American College of Sports Medicine 5, 6.
Topical NSAIDs can be applied PRN or up to 4 times daily to the affected area, with a strength of evidence rated as high for this recommendation 5.
Over-the-counter topicals containing camphor, menthol, or methyl salicylate provide immediate counter-irritant relief and can be applied 3-4 times daily PRN for muscle and soft tissue pain, with moderate evidence supporting their use 9.

Acetaminophen (up to 4 g/day) or oral NSAIDs are appropriate for acute sprain pain and can be used PRN or scheduled, with strong evidence supporting their efficacy for acute pain management 1, 2, 3.

Do not use capsaicin for acute injuries, as the evidence base is exclusively for chronic pain conditions lasting months to years, not acute sprains, a recommendation supported by the American Academy of Orthopaedic Surgeons 1, 2, 3, 4, 5, 6.
Avoid the misconception that "topical = safe for any pain", as capsaicin's mechanism and evidence are highly specific to chronic neuropathic conditions, with low evidence supporting its use for acute sprains 5, 7, 8.