Analgesic

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Analgesic, class of drugs that relieve pain without causing loss of consciousness. The drugs range from the narcotic opium derivatives morphine and codeine (see Opium) to a wide range of nonnarcotics such as aspirin, acetaminophen (Tylenol), and ibuprofen (Advil), the last entering the nonprescription category in the United States in 1984. External analgesics include such drugs as hydrocortisone. Anesthetics in low doses, or local anesthetics such as benzocaine, are also analgesic in function (see Anesthesia).

Narcotics affect the central nervous system, are addictive, and are used only for severe pain; synthetic opiates such as propoxyphene (Darvon), pentazocine (Talwin), and butorphanol (Stadol) are also quite addictive. The nonnarcotics act by inhibiting the synthesis of prostaglandins in the body. Aspirin is a good anti-inflammatory but can irritate the stomach, whereas acetaminophen is less effective against inflammation. Ibuprofen is also an anti-inflammatory, but it can irritate the stomach, as well as aggravate high blood pressure and damage the kidneys. With the discovery of natural opiate receptors in the brain, and of hormones such as endorphins and enkephalins that link to them, research has been devoted to ways in which these systems could be made to ease pain.

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