Fosfenitoína

Fosfenitoína, also known as phenytoin sodium or simply phenytoin, is an antiepileptic medication used primarily to manage and prevent seizures. It belongs to the class of drugs known as hydantoin derivatives and functions by stabilizing neuronal membranes and reducing excessive electrical activity in the brain.

This medication is most commonly prescribed for the treatment of generalized tonic-clonic seizures, focal seizures, and status epilepticus. Fosfenitoína operates by blocking voltage-gated sodium channels, thereby decreasing neuronal excitability and preventing the spread of seizure activity. It is often administered orally in tablet or liquid form, but can also be given intravenously in emergency settings.

Fosfenitoína has a complex pharmacokinetic profile, displaying nonlinear metabolism and a narrow therapeutic window. Monitoring blood plasma levels is essential to ensure efficacy while minimizing adverse effects. Common side effects include dizziness, drowsiness, unsteadiness, and gum overgrowth. More serious but less common adverse effects can involve allergic reactions, cardiac arrhythmias, and severe skin rashes such as Stevens-Johnson syndrome.

The drug's use requires careful dosage adjustment and medical supervision, especially in patients with hepatic impairment or those taking other central nervous system depressants. Drug interactions are also notable, as fosfenitoína can induce or inhibit various metabolic enzymes, affecting the levels of other medications.

Fosfenitoína was first introduced in the mid-20th century and remains a pivotal option in epilepsy management. Its effectiveness and well-documented profile have made it a standard choice; however, newer agents with more favorable side effect profiles are increasingly being used in clinical practice.