Capsaicin

What Is Capsaicin?

Capsaicin is a compound that is found in chili peppers. It is the chemical that is responsible for making peppers taste hot. Capsaicin binds to the sensory receptors of the body that perceive pain. These receptors are known as nociceptors. When capsaicin binds to a nociceptor, it activates this sensory receptor and triggers the sensory neurons to carry signals of pain to the spinal cord and brain. Thus, initial contact with capsaicin leads to sensations of burning, pricking, or even itching. When capsaicin is applied repeatedly or applied in very high concentrations, however, these nociceptors essentially become overwhelmed and the neurons responsible for transmitting pain information are depleted of neurotransmitters. This impedes the function of these sensory neurons in transmitting pain information, thus, causing the compound to have the opposite effect on the sensory system. In other words, repeated exposure to capsaicin or exposure to high concentrations of capsaicin can lead to reductions in pain sensations by temporarily inhibiting the functioning of the sensory neurons.

How Is Capsaicin Treatment Performed?

Capsaicin can be delivered in two ways: applied topically or ingested orally as a dietary supplement. Topical application of medication means that it is applied externally and absorbed through the skin. In most instances, when a medication is applied topically, the effects of this medication are limited to the area surrounding the application site and the body is not able to able to absorb a substantial amount of the medication.

Topical capsaicin may be delivered through the use of topical creams. These creams come in low-concentration (generally 0.075% capsaicin) and high-concentration (generally 8% capsaicin) dosing. While there is little evidence regarding low-concentration capsaicin creams, some studies have found them to be effective in reducing pain. Low-concentration capsaicin creams can be challenging, due to the painful burning experienced upon initial contact, and limited exposure to the active compound of capsaicin itself. Further, patients who are prescribed a low-concentration capsaicin cream are required to apply the medication four times a day, which can lead to problems in terms of the patient’s ability to maintain compliance with the treatment recommendations.

High-concentrated capsaicin cream offers exposure to a higher concentration of capsaicin. Moreover, exposure to higher concentrations of capsaicin means that the nociceptors are overwhelmed more quickly, which can improve the tolerability of the medication. High-concentration capsaicin creams are generally only applied once per day, which also improves patient compliance.

Capsaicin may also be delivered through the use of a dermal patch. These patches are applied directly to the skin and contain about 640 micrograms of capsaicin per square centimeter. These patches are quite convenient, as they can be cut into smaller pieces or even shaped to fit a specified area of the body. Further, patients may put up to four full capsaicin patches together in order to treat larger areas, such as the back. It is important the skin be inspected before applying the patch. Capsaicin patches should never be placed on top of skin that is broken or irritated. Further, given that the concentration of capsaicin in these dermal patches is so high, typically a topical anesthetic (such as a solution of topically applied lidocaine) is used before the capsaicin patch is applied. Thus, the anesthetic is applied and allowed to take effect for around 60 minutes, after which the area is washed and thoroughly dried. The capsaicin patch is then applied and left on the area for anywhere between 30 to 60 minutes, depending on the area of the body that is being treated. Once the capsaicin patch is removed the area must be carefully cleaned. This treatment method may be repeated, if needed, for 12 weeks following the initial treatment.

Conditions Related to Capsaicin Treatments

Damage or dysfunction of the nerve tissue that comprises either the central nervous system or peripheral nervous system can lead to symptoms of neuropathic pain. Symptoms commonly associated with neuropathic pain include:

  • Sharp or stabbing pain
  • Burning sensations
  • Painful tingling
  • Shooting pain
  • Painful sensations similar to an electric shock

Symptoms of neuropathic pain can be acute and time limited, while others may be more persistent. Neuropathic pain is considered chronic in nature when symptoms of pain and discomfort are experienced more days than not over the course of a three-month period.

Capsaicin may be used to treat symptoms of neuropathic pain, particularly in instances where the symptoms are believed to be the result of irritation or injury to the neural tissue of the peripheral nervous system.

Further, there are a number of other chronic pain conditions that may be effectively managed using topical capsaicin, which include:

Capsaicin may also be taken as a dietary supplement. Supplementation with capsaicin may be recommended to improve digestive health. Capsaicin has anti-bacterial properties that can help fight off infections within the digestive tract. For instance, capsaicin may be used to fight infections that lead to symptoms of diarrhea. Capsaicin is also an antioxidant, which protects the body from damage caused by free radicals.

Conclusion

Capsaicin is a natural compound found in chili peppers that binds with the pain receptors of the body known as nociceptors. Initial contact with capsaicin causes these receptors to send signals of pain to the brain; however, repeated exposure or exposure to very high concentrations of capsaicin overwhelms the neuron and impedes its ability to transmit signals of pain.

Capsaicin can be applied topically to treat a number of pain conditions, such as neuropathic pain, joint pain, or even skin conditions. Capsaicin can also be taken orally as a dietary supplement to treat various digestive problems and to fight off bacterial infections. Patients are encouraged to speak with their physician about the risks and benefits associated with the use of capsaicin in the treatment of pain.

References

  1. Anand P, Bley K. Topical capsaicin for pain management. Brit J Anaesthes 2011;107:490-502
  2. Derry S, Rice AS, Cole P, Tan T, Moore RA. Topical capsaicin (high concentration) for chronic neuropathic pain in adults. Cochrane Database of Sys Rev 2013;2: CD010111. doi:10.1002/14651858.CD010111
  3. Anger WH. Low-concentration topical capsaicin for chronic neuropathic pain in adults. Clin J Oncol Nurs 2014;18:123-124
  4. Chrubasik S, Weiser T, Beime B. Effectiveness and safety of topical capsaicin cream in the treatment of chronic soft tissue pain. Phytother Res 2010;24:1877-1885
  5. Robbins W. Clinical applications of capsaicinoids [Review]. Clin J Pain 2000;16:86-89

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