Intramuscular doses also can be given, but the drug does not reach a therapeutic level for 30 minutes.Seizures affect between 4 and 6 % of patients within a week of stroke, and between 2.5 and 6.5 % of patients will develop epilepsy post-stroke. The initial dose of fosphenytoin is 15 to 20 mg PE per kg, so it can be infused at a rate as high as 150 mg PE per minute, a rate of infusion that is three times faster than that of intravenous phenytoin. Because 1.5 mg of fosphenytoin is equivalent to 1 mg of phenytoin, the dosage, concentration, and infusion rate of intravenous fosphenytoin are expressed as phenytoin equivalents (PE). 31 – 34 It is metabolized by the liver and has a half-life of 14 hours.

Fosphenytoin is converted to phenytoin within eight to 15 minutes. Like phenytoin, fosphenytoin is useful in treating acute partial and generalized tonic-clonic seizures. Thus, the adverse events that are related to propylene glycol are avoided. Fosphenytoin is a water-soluble pro-drug of phenytoin that completely converts to phenytoin following parenteral administration. Food and Drug Administration (FDA) in 1996. 16įosphenytoin (Cerebyx) received approval for treatment of status epilepticus from the U.S. Cognitive decline following an episode, as documented by neuropsychometric testing, is a well-established end result of prolonged secondarily generalized and partial status epilepticus. In nonfatal cases, status epilepticus is associated with significant morbidity. 13 – 15 Patients with status epilepticus occurring in the setting of alcohol withdrawal or low levels of antiepileptic drugs had a relatively low mortality rate. 13, 14 Patients with anoxia and stroke had a very high mortality rate that was independent of other variables. 1, 13, 14 The primary determinants of mortality in persons with status epilepticus were duration of seizures, age at onset, and etiology. 1, 13, 14 The elderly population had the highest rate of mortality at 38 percent. 1, 13 The mortality rate among children was only 3 percent, whereas the rate among adults was 26 percent. The rate of mortality from status epilepticus (defined as death within 30 days of status epilepticus) was 22 percent in the Richmond study. In adults, the major causes were low levels of antiepileptic drugs (34 percent) and cerebrovascular disease (22 percent), including acute or remote stroke and hemorrhage. 1 A variety of etiologies accounted for the condition. 1 – 3 Among children 15 years or younger, infants younger than 12 months had the highest incidence and frequency of status epilepticus. 1, 2 Among adults, patients older than 60 had the highest risk of developing status epilepticus, with an incidence of 86 per 100,000 persons per year. The incidence of status epilepticus was bimodally distributed, occurring most frequently during the first year of life and after the age of 60 years. 1 – 4, 8 – 12 One epidemiologic study 1 on status epilepticus found that 69 percent of episodes in adults and 64 percent of episodes in children were partial onset, followed by secondarily generalized status epilepticus in 43 percent of adults and 36 percent of children.

Status epilepticus of partial onset accounts for the majority of episodes. Physicians should rely on a standardized protocol for management of status epilepticus to improve care for this neurologic emergency. In patients with persistent alteration of consciousness for which there is no clear etiology, physicians should be more quickly prepared to obtain electroencephalography to identify status epilepticus. Moreover, investigators have reported that status epilepticus often is not considered in patients with altered consciousness in the intensive care setting. Despite the paucity of clinical trials comparing medication regimens for acute seizures, there is broad consensus that immediate diagnosis and treatment are necessary to reduce the morbidity and mortality of this condition. However, randomized controlled trials show that benzodiazepines (in particular, diazepam and lorazepam) should be the initial drug therapy in patients with status epilepticus. Three new preparations-fosphenytoin, rectal diazepam, and parenteral valproate-have implications for the management of status epilepticus. Treatment is evolving as new medications become available. Status epilepticus is associated with a high mortality rate that is largely contingent on the duration of the condition before initial treatment, the etiology of the condition, and the age of the patient. Status epilepticus is an increasingly recognized public health problem in the United States.

Types of seizures and durations