Capsaicin Ointment for Neuropathic Pain

Capsaicin Ointment for Neuropathic Pain

Capsaicin, the active component of chili peppers, is utilized in topical formulations to manage neuropathic pain, a condition often characterized by hypersensitivity and chronic pain due to nerve damage. Capsaicin ointments and patches work by desensitizing sensory neurons, providing relief from pain.

Mechanism of Action

Capsaicin acts on the transient receptor potential vanilloid 1 (TRPV1), which is expressed in the central and peripheral terminals of sensitive primary nerve cells. When applied topically, capsaicin initially causes enhanced sensitivity to noxious stimuli, followed by a period of reduced sensitivity and, after repeated applications, persistent desensitization of the nociceptors [1].

Efficacy of Capsaicin in Treating Neuropathic Pain

• Low Concentration Capsaicin Creams (0.075%):
  
  • A Cochrane review included six studies with 389 participants comparing low-dose capsaicin cream to placebo. The number needed to treat (NNT) for any pain relief over six to eight weeks was 6.6, indicating that one in every 6.6 patients would benefit from the treatment [2].
  • Local skin reactions were common but usually tolerable and decreased over time. The number needed to harm (NNH) for local skin reactions was 2.5 [2].
  • However, another review suggested that the data were insufficient to conclude the efficacy of low-concentration capsaicin cream in treating neuropathic pain, citing a lack of robust evidence [3].
• High Concentration Capsaicin Patches (8%):
  
  • Studies have shown that a single application of a high-dose capsaicin patch can provide significant pain relief for conditions such as postherpetic neuralgia and HIV neuropathy. The NNT for ≥30% pain relief over twelve weeks was 12 [2].
  • The high-concentration capsaicin patch must be applied under controlled conditions, often following local anesthesia, due to the intense burning sensation it can cause initially [4].
  • A review including six studies with 2073 participants found that high-concentration topical capsaicin generated more participants with moderate or substantial levels of pain relief than control treatment [5].

Application and Tolerability

• Topical Application:
  
  • Capsaicin cream is typically applied several times daily to the affected area. The skin should be intact, without any cuts or abrasions, to prevent excessive burning sensations [6].
  • For the capsaicin patch, a single application is given and is expected to last for about 12 weeks. The patch must be applied by a healthcare professional [4].
• Tolerability:
  
  • While local skin reactions such as burning or redness are common, they are generally mild and transient. Systemic adverse effects are rare [2].
  • In some cases, pretreatment with a topical anesthetic like lidocaine may be used to reduce discomfort during the application of the capsaicin patch [7].

Clinical Considerations and Patient Education

• Patient Selection:
  
  • Capsaicin treatment is suitable for patients with localized neuropathic pain who have not responded adequately to other pain management strategies [8].
  • It is important to assess the patient's pain characteristics, as certain types of pain may respond better to capsaicin treatment [9].
• Patient Education:
  
  • Patients should be informed about the potential for initial discomfort and the importance of regular application as prescribed [1].
  • They should be advised to wash their hands thoroughly after applying capsaicin cream to avoid accidental contact with the eyes or mucous membranes [6].

Conclusive Summary

Capsaicin ointment, available in low and high concentrations, is a valuable treatment option for neuropathic pain. Its efficacy is supported by clinical studies, although the evidence is stronger for high-concentration patches. Patients should be counseled on the correct application and potential side effects, and healthcare providers should monitor treatment response and tolerability. Capsaicin treatment can offer significant pain relief and improve the quality of life for patients suffering from chronic neuropathic pain.

References:

1. A Sultana et al. Topical Capsaicin for the Treatment of Neuropathic Pain. Current drug metabolism (2020).
2. S Derry et al. Topical capsaicin for chronic neuropathic pain in adults. The Cochrane database of systematic reviews (2009).
3. S Derry et al. Topical capsaicin (low concentration) for chronic neuropathic pain in adults. The Cochrane database of systematic reviews (2012).
4. S Derry et al. Topical capsaicin (high concentration) for chronic neuropathic pain in adults. The Cochrane database of systematic reviews (2013).
5. S Derry et al. Topical capsaicin (high concentration) for chronic neuropathic pain in adults. The Cochrane database of systematic reviews (2017).
6. JB Epstein et al. Topical application of capsaicin for treatment of oral neuropathic pain and trigeminal neuralgia. Oral surgery, oral medicine, and oral pathology (1994).
7. KU Kern et al. Treatment of neuropathic pain with the capsaicin 8% patch: is pretreatment with lidocaine necessary?. Pain practice : the official journal of World Institute of Pain (2013).
8. SE Thomas et al. The use of high dose topical capsaicin in the management of peripheral neuropathy: narrative review and local experience. British journal of pain (2020).
9. M Sendel et al. Capsaicin treatment in neuropathic pain: axon reflex vasodilatation after 4 weeks correlates with pain reduction. Pain (2022).

The information contained in this blog post is for educational and informational purposes only. They are not intended to diagnose, treat or prevent any medical condition. Always consult your doctor before making any decisions about your health, including changes in treatment.