Which medication is a potential treatment for seizure disorders?

Phenytoin is a well-established medication used for the management of seizure disorders, specifically for controlling tonic-clonic seizures and complex partial seizures. It works by stabilizing the neuronal membrane and preventing the abnormal electrical discharges that lead to seizures. As an anticonvulsant, phenytoin is especially utilized in both acute treatment and long-term management of epilepsy.

The other medications listed serve different purposes: alprazolam is primarily used for anxiety disorders and does have some sedative effects, but it is not primarily indicated for seizure treatment. Levothyroxine is a thyroid hormone replacement therapy used for hypothyroidism, and metformin is an oral hypoglycemic agent used in the management of type 2 diabetes. Thus, phenytoin stands out as the appropriate choice for treating seizure disorders.