narcotic (narc) /narkot″ik/ [Gk, narkotikos, benumbing] , 1. adj., pertaining to a substance that produces insensibility or stupor. 2. n., a narcotic drug. Narcotic analgesics, derived from opium or produced synthetically, alter perception of pain; induce euphoria, mood changes, mental clouding, and deep sleep; depress respiration and the cough reflex; constrict the pupils and cause smooth muscle spasm, decreased peristalsis, emesis, and nausea. Repeated use of narcotics may result in physical and psychological dependence. Among the narcotic drugs administered clinically for relief of pain are butorphanol tartrate, hydromorphone hydrochloride, morphine sulfate, pentazocine lactate, and meperidine hydrochloride. These drugs act by binding to opiate receptors in the central nervous system; narcotic antagonists such as naloxone hydrochloride, which is used in treating narcotic overdosage, apparently displace opiates from receptor sites. The term is now often used to refer to any illicit drug, and its use is therefore discouraged in medical settings. Opioid is now the preferred term.
