Fosphenytoin is an anticonvulsant used for generalized convulsive status epilepticus to prevent treatment of seizures during surgery. Fosphenytoin is a water soluble phenytoin prodrug, it acts by slowing down impulses in the brain reducing neuronal activity and avoiding a seizure. It blocks neuronal sodium channels to limit repetitive firing of action potentials. Once administered fosphenytoin is acted upon by endogenous phosphatases to be converted into phenytoin that acts to apply the anticonvulsant properties and inhibit channel activity. It inhibits by promoting sodium efflux which stabilizes the channel against hyperexcitability. It is excreted through the urine as 5-phenylhydantoin. Adverse effects that could come from administration is nausea, vomiting, lethargy, tachycardia, bradycardia, cardiovascular complications, metabolic acidosis and in some cases overdosage can result in death.

Fosphenytoin References