A derivative of barbituric acid, including phenobarbital and others, that act as CNS depressants and are used for their tranquilizing, hypnotic, and anti-seizure effects; most barbiturates have the potential for abuse.
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1) a salt or ester of barbituric acid
2) any of various derivatives of barbituric acid (as phenobarbital) that are used esp. as sedatives, hypnotics, and antispasmodics and are often addictive
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n.
any of a group of drugs, derived from barbituric acid, that depress activity of the central nervous system and were formerly widely used as sedatives and hypnotics. They are classified into three groups according to their duration of action - short, medium, and long. Because they produce tolerance and psychological and physical dependence, have serious toxic side-effects (see barbiturism), and can be fatal following large over-dosage, barbiturates have been largely replaced in clinical use by safer drugs. The main exception is the very short-acting drug thiopental, which is used to induce anaesthesia. See also amobarbital, butobarbital, phenobarbital.
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bar·bi·tur·ate (bahr-bichґər-ət) any of a class of sedative-hypnotic agents derived from barbituric acid or thiobarbituric acid and classified into long-, intermediate-, short-, and ultrashort-acting classes. The ultrashort-acting barbiturates, e.g., thiopental, are used as intravenous anesthetics. The long-acting barbiturate phenobarbital is an important anticonvulsant used in the treatment of epilepsy. Many other barbiturates were widely used as sedatives or hypnotics, but benzodiazepines have replaced them in most uses. Some of these have a high potential for abuse.Medical dictionary. 2011.