Several types exist and work in different ways depending on the ingredients. Salicylates are a family of drugs that reduce inflammation and pain. They come from the bark of the willow tree and are the pain relieving substance found in aspirin. Small amounts relieve mild pain. Larger amounts may reduce both pain and inflammation.
Salicylates decrease the ability of the nerve endings in the skin to sense pain.
Irritants, another type of topical ingredient, stimulate nerve endings in the skin to cause feelings of cold, warmth, or itching, which avert attention from the actual pain. Some topical pain relievers are methyl salicylate, menthol, camphor, eucalyptus oil, turpentine oil, histamine dihydrochloride, and methyl nicotinate. Capsaicin, a substance found in hot peppers, reduces the amount of the chemical substance P, which sends pain signals to the brain. Temporary relief of pain from RA and OA occurs within two to four weeks. Capsaicin is applied three to four times daily.