A counterirritant is a substance which creates irritation or mild inflammation in one location with the goal of lessening discomfort and/or inflammation in another location. This strategy falls into the more general category of
counterstimulation
Counterstimulation is a treatment for pain based on distraction.
A basic example is the practice of rubbing a fresh bruise, so that attention is paid to the sense of touch and pressure, rather than to the pain of the injury. Liniment and "medicate ...
.
Topical counter-irritants are non-analgesic, non-anesthetic substances or treatments used to treat pain.
Capsaicin,
menthol
Menthol is an organic compound, more specifically a monoterpenoid, made synthetically or obtained from the oils of corn mint, peppermint, or other mints. It is a waxy, clear or white crystalline substance, which is solid at room temperature and ...
(mint oil),
methyl salicylate, and
camphor
Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel ('' Cinnamomum camphora''), a large evergreen tree found in East Asia; and in the k ...
are examples of counterirritants. Heat and cold therapy and massage relieve pain by counterstimulation.
The US
Food and Drug Administration defines a counterirritant as "An externally applied substance that causes irritation or mild inflammation of the skin for the purpose of relieving pain in muscles, joints and viscera distal to the site of application. They differ from the
anesthetics,
analgesic
An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...
s, and
antipruritic
Antipruritics, abirritants, or anti-itch drugs, are medications that inhibit the itching (Latin: ''pruritus'') often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, fungal infections, insect bites and stings like those ...
agents, however, in that the pain relief they produce results from stimulation—rather than
depression—of the cutaneous sensory receptors and occurs in structures of the body other than the skin areas to which they are applied as for example, in joints, muscles,
tendons and certain viscera. The use of these products dates from antiquity."
References
Pain management
Neuropharmacology
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