What are cayenne's therapeutic uses?

Overview

Cayenne and related peppers have a long history of use as digestive aids in many parts of the world, but the herb’s recent popularity has come through conventional medicine. The capsicum family includes red peppers, bell peppers, pimento, and paprika, but the most famous medicinal member of this family is the common cayenne pepper.

Requirements and Sources

Many people think that hot peppers cause inflammation of tissues and that this is the source of the classic hot pepper sensation. However, hot peppers do not actually have any damaging effect; they merely simulate the sensations produced by damage. (Herbs such as garlic, ginger, horseradish, and mustard actually can cause tissue damage.)

Therapeutic Dosages

Capsaicin creams are approved over-the-counter drugs and should be used as directed. If the burning sensation that occurs with initial use is too severe, using weaker forms of the cream at first may be advisable. For treatment of dyspepsia, cayenne may be taken at a dosage of 0.5 to 1.0 grams (g) three times daily (prior to meals).

Therapeutic Uses

All hot peppers contain a substance called capsaicin. When applied to tissues, capsaicin causes release of a chemical called substance P. Substance P is ordinarily released when tissues are damaged; it is part of the system the body uses to detect injury. When hot peppers artificially elicit the release of substance P, they trick the nervous system into thinking that an injury has occurred. The result: a sensation of burning pain.

When capsaicin is applied regularly to a part of the body, substance P becomes depleted in that location. This is why individuals who consume a lot of hot peppers gradually build up a tolerance.

It is also the basis for a number of medical uses of capsaicin. When levels of substance P are reduced in an area, all pain in that area is somewhat reduced. Because of this effect, capsaicin cream is widely used for the treatment of various painful conditions.

Under the brand name Zostrix, a cream containing concentrated capsaicin has
been approved by the U.S. Food and Drug Administration for
the treatment of post-herpetic neuralgia, the pain that often lingers after an
attack of shingles. There is also relatively good evidence that
topical capsaicin can modestly decrease the pain of diabetic peripheral
neuropathy, other forms of peripheral neuropathy nerve pain following cancer
surgery, as well as the pain of arthritis. Capsaicin cream may also be helpful for
other forms of pain, including fibromyalgia, back pain, and cluster headaches.
However, the benefits seen with capsaicin are seldom dramatic; in many cases,
other pain-relieving treatments are used simultaneously. Besides pain-related
conditions, some evidence indicates that topical capsaicin may be helpful for
psoriasis and possibly other skin conditions as well (especially those that
involve itching).

Cayenne can be taken internally as well. It appears that oral use of cayenne
might reduce the pain of minor indigestion (dyspepsia). This may seem
like an odd use of the herb; intuitively, it seems that hot peppers should be hard
on the stomach. However, remember that hot peppers do not actually damage tissues;
they merely produce sensations similar to those caused by actual damage.
Apparently, by depleting substance P in the stomach, they reduce sensations of
discomfort. In fact, some evidence suggests that oral use of cayenne or capsaicin
can actually protect the stomach against ulcers caused by anti-inflammatory
drugs. However, contrary to some reports, cayenne does not
appear to be able to kill Helicobacter pylori, the stomach
bacterium implicated as a major cause of ulcers. In addition, it appears that,
contrary to long- standing belief, hot peppers do not cause increased pain in
people with hemorrhoids.

Scientific Evidence

Oral uses of cayenne. In a double-blind, placebo-controlled study, thirty individuals with dyspepsia were given either 2.5 g daily of red pepper powder (divided up and taken prior to meals) or a placebo for five weeks. By the third week of treatment, individuals taking red pepper were experiencing significant improvements in pain, bloating, and nausea compared with a placebo, and these relative improvements lasted through the end of the study. A placebo-controlled, crossover study failed to find benefit, but it only enrolled eleven participants, far too few to have much chance of identifying a treatment effect.

Topical uses of cayenne. All double-blind studies of topical capsaicin (or cayenne) suffer from one drawback: It is not really possible to hide the burning sensation that occurs during initial use of the treatment. For this reason, such studies probably are not truly double-blind. It has been suggested that instead of an inactive placebo, researchers should use some other substance (such as camphor) that causes at least mild burning. However, such treatments might also have therapeutic benefits; they have a long history of use for pain as well. Because of these complications, the evidence for topical treatments cited here is less meaningful than it might at first appear.

Capsaicin cream is well established as a modestly helpful pain-relieving treatment for post-herpetic neuropathy (the pain that lingers after an attack of shingles), peripheral neuropathy (nerve pain that occurs most commonly as a complication of diabetes, but may occur with human immunodeficiency virus infection and other conditions), pain after surgery for cancer or hernia repair, and osteoarthritis.

Weaker evidence supports the use of topical capsaicin for fibromyalgia. Capsaicin instilled into the nose may be helpful for cluster headache.

Actual cayenne rather than capsaicin has been tested for pain as well. A three-week double-blind trial of 154 individuals with back pain found that cayenne applied topically as a “plaster” improved pain to a greater extent than a placebo.

A double-blind, placebo-controlled trial of nearly two hundred individuals
found that use of topical capsaicin can improve itching as well as overall
severity of psoriasis. Benefits were also seen in a smaller double-blind
study of topical capsaicin for psoriasis. Topical capsaicin is thought to be
helpful for various itchy skin conditions, such as prurigo nodularis, but
double-blind studies are lacking.

Intranasal uses of cayenne. One study of 208 patients with idiopathic rhinitis found that using a capsicum nasal spray three times daily for three days (4 micrograms per puff) may reduce symptom frequency.

Safety Issues

Capsaicin creams commonly cause an unpleasant burning sensation when they are first applied; this sensation disappears over subsequent days as treatment is continued. As a commonly used food, cayenne is generally recognized as safe. Contrary to some reports, cayenne does not appear to aggravate stomach ulcers.

Important Interactions

Cayenne might increase the amount of absorption of the asthma drug
theophylline, possibly leading to toxic levels. However,
cayenne might protect the stomach from damage caused by nonsteroidal anti-inflammatory
drugs.

Bibliography

Alper, B. S., and P. R. Lewis. “Treatment of Postherpetic Neuralgia: A Systematic Review of the Literature.” Journal of Family Practice 51 (2002): 121-128.

Bortolotti, M., et al. “The Treatment of Functional Dyspepsia with Red Pepper.” Alimentary Pharmacology and Therapeutics 16 (2002): 1075-1082.

Frerick, H., et al. “Topical Treatment of Chronic Low Back Pain with a Capsicum Plaster.” Pain 106 (2003): 59-64.

Jensen, P. G., and J. R. Larson. “Management of Painful Diabetic Neuropathy.” Drugs and Aging 18 (2001): 737-749.

McCleane, G. “Topical Application of Doxepin Hydrochloride, Capsaicin, and a Combination of Both Produces Analgesia in Chronic Human Neuropathic Pain.” British Journal of Clinical Pharmacology 49 (2000): 574-579.

Rodriguez-Stanley, S., et al. “The Effects of Capsaicin on Reflux, Gastric Emptying, and Dyspepsia.” Alimentary Pharmacology and Therapeutics 14 (2000): 129-134.

Stander, S., T. Luger, and D. Metze. “Treatment of Prurigo Nodularis with Topical Capsaicin.” Journal of the American Academy of Dermatology 44 (2001): 471-478.

Todd, C. “Meeting the Therapeutic Challenge of the Patient with Osteoarthritis.” Journal of the American Pharmaceutical Association 42 (2002): 74-82.