Is a hydantoin whose chemical structure is closely related to that of barbiturates. is one of the drugs most commonly used to control epileptic seizures in the United States and around the world. is prescribed to treat various types of convulsions and seizures, including generalized tonic–clonic (grand mal), complex partial (psychomotor, temporal lobe) seizures, status epilepticus, non-epileptic seizures associated with Reye syndrome or after head trauma, and Bell’s palsy.