methaqualone
n. a synthetic drug with sedative and hypnotic effects, unrelated chemically to other sedatives and having a potency roughly equal to that of pentobarbital. It is used to treat patients who are unable to tolerate barbiturate drugs. In small doses, the drug depresses the sensory cortex; in larger doses, it affects the spinal reflexes. Its clinical use peaked during the 1960s and 1970s, but due to its potential for abuse—it became a popular recreational drug (street name: lude)—it was classified as a Schedule I controlled substance in 1984, which ended its legal availability in the United States. Trade name (among others): Quaalude. See sedative, hypnotic, and anxiolytic drug.