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one of a group of medicinal preparations having different chemical compositions and capable of preventing or relieving convulsions. Anticonvulsants include a number of substances that act as hypnotics and sedatives, for instance, bromides, chloral hydrate, magnesium sulfate, and phenobarbital. Other substances are selectively anticonvulsant, for example, diphenin, Hexamidine (lepsiral), Trimethin (epidione), and chloracon. Anticonvulsants are used mainly in treating epilepsy.