Capsicum Information - Drug Interactions, Uses and Benefits
Taxonomic Class
Solanaceae
Common Trade Names
Capsin, Cap-Stun, Capzasin, Dolorac, No Pain HP, Pepper Defense, RGel, Zostrix (HP)
Common Forms
Cream: 0.025%, 0.075%, 0.25%
Gel: 0.025%
Lotion: 0.025%, 0.075%
Self-defense spray: 5%,10%
Source
Capsaicinoids are derived from the dried fruit of the plants of the Solanaceae family. The species most commonly used are Capsicum frutescens and Capsicum annum. Before the actual capsaicin can be isolated, a concentrate called oleoresin capsicum is formed from the peppers. Extraction of capsaicin forms water-insoluble needles (highlyalcohol- and fat-soluble). Other species of Capsicum used include C. baccatum, C. chinensis, and C. pubescens. These peppers should not be confused with the plants that give us common black pepper and white pepper (Piper species, family Piperaceae).
Chemical Components
Capsicum species can contain up to 1.5% of a capsaicinoid oleoresin. The major components of the oleoresin responsible for the plant's pungent appeal are capsaicin, 6,7-dihydrocapsaicin, homocapsaicin, homodihydrocapsaicin, and nordihydrocapsaicin. Many volatile oils, carotenoids (capsanthin, capsorubin, carotene, lutein), proteins, fats, and high amounts of vitamins A and C are present. The amount of vitamin C present may be four to six times that found in an orange. Provitamins E, P, B1, B2 and B3 have also been identified as components.
Other plant material contains steroidal alkaloidal glycosides (solanine and solasadine) and scopoletin (coumarin). Each chili pepper contains about 0.14% of capsaicin, with the highest concentrations in the yellowish red placenta of the fruit and its attachments.
Actions
Although topical capsaicin produces an intense irritation at the contact point, vesicles usually do not form. The initial dose of capsaicin causes profound pain, but repeated applications produce desensitization, with analgesic and even anti-inflammatory effects. Heat sensation is caused by the stimulation of specific local afferent nerve fibers. Analgesic effects may be explained by capsaicin-induced neuronal depletion of substance P, believed to be a mediator in the transmission of painful stimuli from the periphery to the spinal cord. The analgesic effect can also result from the methoxyphenol portion of the capsaicin molecule that may interfere with the lipoxygenase and cyclooxygenase pathways.
Capsaicin does not cause blistering or redness because it does not act on the capillaries or other blood vessels. An externally applied 0.1 % capsaicin solution inhibits flare formation after intradermal injection of histamine. Areas of skin (control) without pretreatment of capsaicin developed a wheal, flare, and itching. Flare response is believed to be substance P-mediated.
Juices from the fruits have shown antibacterial properties in vitro. I.V. infusion of capsaicin has been reported to stimulate secretion of epinephrine and norepinephrine from the adrenal medulla of rodents.
Reported Uses
Traditional claims surrounding the use of capsicum include treatment of bowel disorders, chronic laryngitis, and peripheral vascular disease. Various preparations of capsicum have been applied topically as counterirritants and external analgesics. Topical capsaicin preparations are useful for treating pain associated with diabetic neuropathy, osteoarthritis, postherpetic neuralgia postsurgical pain (including postmastectomy and postamputation pain), rheumatoid arthritis, and other neuropathic pain and complex pain syndromes
Capsaicin has been suggested for refractory pruritus and pruritus associated with renal failure. A small study has suggested that nasal inhalation of capsaicin may be beneficial in nonallergic, noninfectious perennial rhinitis. Poor tolerability may be of issue with larger clinical trials. One study has reported capsaicin's use for urinary urgency. Capsaicin is also increasingly popular as a nonlethal self-defense spray.
Dosage
Because capsaicin is potent, concentrations of topical preparations range from 0.025% to 0.25%. Preparations are most effective when applied t.i.d. or q.i.d., and their duration of action is 4 to 6 hours. Less frequent application typically produces less effective substance P depletion and results in incomplete analgesia.
Adverse Reactions
CNS: neuropathy.
EENT: blepharospasm, conjunctival edema, extreme burning pain in eye, hyperemia, lacrimation (ocular complications arc rare and usually result from eye rubbing); burning pain in nose, serous nasal discharge, sneezing.
GI: GI discomfort (minimized if seeds are removed from the product before ingestion).
GU: renal dysfunction (when used orally on a regular basis).
Hematologic: deficient coagulability, RBC hemolysis.
Hepatic: hepatic dysfunction (when used orally on a regular basis).
Respiratory: transient bronchoconstriction, cough, and retrosternal discomfort.
Skin: transient erythema, irritation, itching, and stinging without vesicular eruption (diminishes with repeated use).
Interactions
ACE inhibitors: Topical application of capsicum may contribute to the cough reflex. Avoid administration with capsicum.
Anticoagulant and antiplatelet properties: May increase hypocoagulability when used concurrently with such drugs as warfarin and acetylsalicylic acid. Avoid administration with capsicum.
Centrally acting adrenergic agents: May reduce efficacy of antihypertensives such as clonidine and methyldopa. Avoid administration with capsicum.
MAO inhibitors: May promote toxicity (hypertensive crisis) when used together because of catecholamine release. Avoid administration with capsicum.
Sedatives: Concomitant use may cause additive therapeutic and adverse effects. Use together cautiously.
Contraindications And Precautions
Contraindicated in patients who are hypersensitive to capsicum or chili pepper products. Also contraindicated in pregnant patients to avoid possible uterine stimulant effects.
Special Considerations
The intensity of adverse reactions depends on the dose and concentration.
Alert topical application of capsicum to open wounds or injured skin, relief can occur in as little as 3 days but may take 14 to 28 days, depending on the condition that requires analgesia.
No evidence exists that topical application causes permanent neurologic injury.
Dose-related (1 to 100 nM) RBC hemolysis associated with significant changes in erythrocyte membrane lipid components as well as acetylcholinesterase activity can occur.
Instruct the patient to avoid contact with eyes, mucous membranes, and nonintact skin. Direct him to flush the exposed area with cool running water for as long as necessary if incidental contact occurs.
Caution the patient taking MAO inhibitors or centrally acting adrenergics against using capsicum.
Advise women to avoid using capsicum during pregnancy or when breast-feeding.
Instruct the patient not to use other heat applications simultaneously with capsicum.
Points of Interest
More than one-third of its total vitamin C content remains after a chili pepper has been cooked; vitamin C is lost if the pepper is dried.
Because of its short-term immobilizing effects, capsaicin is used as a humane self-defense spray. The more popular products contain the capsicum oleoresin, which produces immediate blepharospasm, blindness, and incapacitation for up to 30 minutes.
Peppers are among the most widely consumed spice in the world with an average per-person consumption approaching 50 mg of capsaicin daily in some Southeast Asian countries.
Commentary
Natural capsicum has been used for centuries. Capsaicin, derived from capsicum, has gained widespread popularity as an agent for several potential therapeutic applications. Commercially available capsaicin preparations are effective adjunctive topical analgesics for some pain and pruritic syndromes. Long-term effects of topical application appear benign. For some patients, the initial burning sensation and delayed onset of action may be the most undesirable aspects of its use. The ingestion of capsicum in excess of the amount normally available in food is not recommended.
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