Analgesic

Capsaicin

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Capsaicin, Zostrix

  • Mechanism
  1. Capsaicin is derived from chili peppers (genus Capsicum) such as jalapeno peppers
  2. Capsaicin is a Transient Receptor Potential Vanilloid 1 (TRPV1) agonist
    1. TRPV1 activates cation channels on pain nerve fibers (nociceptive fibers)
    2. Nociceptive nerves depolarize, transmitting pain signal to the spinal cord
  3. Capsaicin depletes Substance P from pain fibers, desensitizing nerves and preventing pain transmission
    1. Requires frequent and repeat applications for effect
    2. Inconsistent use is not effective
  • Dose
  • Capsaicin Cream (OTC)
  1. Neuropathic pain
    1. Apply Capsaicin cream as a thin film (0.025% to 0.075%) to affected area 3-4 times daily
  2. Cannabinoid Hyperemesis Syndrome (off label)
    1. Apply Capsaicin cream as a thin film (0.075%) to 15 x 25 cm periumbilical area every 4 hours until symptoms resolve
  • Dose
  • Capsaicin Patch (high dose - 8%)
  1. Applied in office
  2. Pre-treat area by applying 4% Lidocaine cream for 60 minutes
  3. Check area for Anesthesia following application
  4. Apply Capsaicin 8% cream with gloves and leave on for 60 minutes
  5. Wash off after 1 hour
  • Adverse effects
  1. Local Irritation
    1. Erythema (63%)
    2. Burning Sensation (42%)
      1. Most significant on initial application
    3. Less commonly, Pruritus, edema and local swelling
  2. Increased pain for up to first week of application
  • Precautions
  1. Wash hands thoroughly after Capsaicin application