In small doses narcotics have valuable medical uses, numbing the senses, relieving severe pain, and inducing sleep. They are also given preoperatively to relieve pain and anxiety. Common side effects include constipation, nausea, and allergic reactions. In large doses narcotics can be highly dangerous, causing stupor, coma, convulsions, or death. All narcotics are addictive; several morphine derivatives as well as chemically dissimilar narcotics that have been developed for medical use have fewer side effects and are less addictive than morphine, but they are also generally less potent. Unlike general anesthetics such as ether and chloroform, narcotics depress the respiratory center and in low doses relieve pain without inducing sleep. Respiratory depression occurs in newborns whose mothers have been given narcotics such as meperidine (Demerol) during labor. Narcotics differ from barbiturates and other sedatives in that they have no anticonvulsant action; also, narcotics relieve pain, while sedatives do not.