Capsaicin

Capsaicin

Definition

Capsaicin is the active ingredient in chili peppers, the substance that gives chili and cayenne its heat.

Purpose

Research on the use of capsaicin for cancer patients has focused on several areas:

• its ability to decrease pain
• its potential to be carcinogenic
• any chemoprotective capacity
• any antimicrobial and detoxification properties

Description

Folk accounts of capsaicin's medicinal properties in the form of cayenne have included aiding digestion, promoting the sweating process to create cooling (for reducing a fever ), fighting infections, and stimulating the function of the kidneys, lungs, stomach, and heart. Research on capsaicin's ability to decrease pain has been in the areas of chronic pain, arthritic pain, migraine pain, and neuropathic cancer pain. It appears to interfere with chemicals that facilitate pain messages to the brain. Capsaicin has a hyperemic effect, which means that it increases blood flow similar to when an area is inflamed. When applied to the skin in cream form, the area becomes red, warm, and may become slightly swollen. Many individuals experience a localized burning sensation when a cream containing capsaicin is applied to the skin. However, with repeated use, the burning sensation usually disappears, and pain relief is noted. The burning or stinging sensation may last a few weeks for some. Capsaicin appears to work through a mechanism that initially causes a hypersensitivity to pain, and then ends in pain relief.

Several clinical studies performed on the effectiveness of various formulations of capsaicin have demonstrated that a majority of patients experience a reduction in pain and few or minor side effects. Capsaicin has been reported to have an effect against H. pylori, and also some antimicrobial properties. It appears to protect the lining of the digestive tract from harm due to aspirin use. Capsaicin has also showed an inhibitory effect on skin carcinogenesis in mice and a suppression of proliferation of human cancer cells.

Early studies on capsaicin raised the concern that capsaicin could be carcinogenic. However, further studies reported that capsaicin was not carcinogenic, and in fact might have chemoprotective properties. Studies investigating its potential to promote tumor development indicate it does not have this ability.

Recommended dosage

The Physician's Desk Reference (PDR) for Herbal Medicines indicates the availability of the following dosages of cayenne:

• Capsules: 400, 445, 450, 455, and 500 mg strengths
• Cream containing 0.25% and 0.75% capsaicin
• Liquid alcohol-based extract

The average daily dose in capsule form for cayenne (capsicum annum) is 30 to 120 mg. Individuals wishing to use capsaicin should do so under the guidance of a practitioner knowledgeable about its properties, to ensure proper monitoring for any adverse reactions.

Precautions

Capsaicin's fiery nature requires some precautions to be used when handling it in its natural form or when applying it topically as a cream. Thorough hand washing after contact with it is necessary, as it can cause an intense burning or stinging sensations. Avoid any contact with mucous membranes, such as eyes or mouth, or any open wounds, until hands have been washed. Bottles storing capsaicin or cayenne should be well sealed and kept out of the light. It should not be refrigerated.

The National Cancer Institute (NCI) cautions that it is not known whether capsaicin used by a breast feeding mother will pass into the breast milk. Individuals who have had an allergic reaction to hot peppers should speak to their health care provider before using capsaicin. Some individuals may experience a prolonged burning sensation with topical capsaicin. However, the NCI states that reducing the number of doses per day will not result in decreasing the sensation, and may prolong the time period over which the sensation is experienced. In addition, a reduction in the number of doses may also reduce the degree of pain relief. Patients taking capsaicin should not double-up on a dose if a dose is missed.

Side effects

Research on capsaicin is still in the early stages, but the following has been reported:

• hypersensitivity reaction such as anaphylaxis and rhinoconjunctivitis
• abnormal blood clotting ability
• an increase in bowel function, leading to diarrhea
• blister formation on the skin
• contact dermatitis
• increase in cough with extended exposure to chili peppers
• long-term use of high dosages can lead to kidney and liver damage, chronic gastritis, and neurotoxic effects

Interactions

If aspirin and capsicum annum extract (in the form of 100 mg of capsaicin) are taken at the same time, decreased bioavailability of aspirin may occur. This treatment may interfere with MAO inhibitors and antihypertensive therapy. As with any medication, patients should notify their physician of any prescription, over-the-counter, or herbal remedies they are taking prior to receiving treatment.

Resources

INFORMATION ON CLINICAL STUDIES

Anesthesia and Analgesia 86, no. 3 (March 1998): 579-83.

Annals of the New York Academy of Sciences 889 (1999): 157-92.

Cancer Letters 120, no. 2 (9 December 1997): 235-41.

Cancer Letters 164, no. 2 (26 March 2001): 119-26

Mutation Research 428, no. 1-2 (16 July 1999): 305-27.

Esther Csapo Rastegari, R.N., B.S.N., Ed.M.

KEY TERMS

Bioavailability.

—A term used in describing the amount of a medication taken that is actively available to the targeted body area. Bioavailability can be affected by factors such as the rate at which a tablet or capsule dissolves, binding products using in formulating the medication, and the person's ability to break down and use the medication.

Carcinogenic

—A substance that can cause cancer to develop.

Mucositis.

—An inflammation of the lining of the digestive tract, often accompanied by mouth and throat lesions.

Neuropathic pain.

—Pain that is felt near the surface of the skin, along nerve pathways.

Neurotoxic.

—A substance that is harmful to the nervous system.