Phenytoin

Phenytoin is classified as a hydantoin derivative and despite its narrow therapeutic index, it is one of the most commonly used anticonvulsants. Since it's introduction about 80 years ago, phenytoin has not only been established as an effective anti-epileptic, but has also been investigated for several other indications such as bipolar disorder, retina protection, and wound healing.

Clinicians are advised to initiate therapeutic drug monitoring in patients who require phenytoin since even small deviations from the recommended therapeutic range can lead to suboptimal treatment, or adverse effects. Both parenteral and oral formulations of phenytoin are available on the market.

Phenytoin is indicated to treat grand mal seizures, complex partial seizures, and to prevent and treat seizures during or following neurosurgery. Injectable phenytoin and Fosphenytoin, which is the phosphate ester prodrug formulation of phenytoin, are indicated to treat tonic-clonic status epilepticus, and for the prevention and treatment of seizures occurring during neurosurgery.