Antiseizure Medications

Antiseizure medications reduce excessive neuronal firing and help prevent recurrent seizures. They are not interchangeable, and they are not automatically indicated for every episode of altered consciousness. The first clinical question is what happened: a focal seizure, a generalized tonic-clonic seizure, a medication effect, hypoglycemia, syncope, or another neurologic event. Epilepsy is diagnosed after either: - at least two unprovoked seizures occurring more than 24 hours apart; or - one unprovoked seizure when the estimated risk of recurrence is greater than 60% over the next 10 years, after acute symptomatic causes have been excluded. A seizure caused by a reversible acute problem, such as hypoglycemia or acute intoxication, does not by itself establish epilepsy. That distinction matters because the immediate treatment may be correction of the cause rather than indefinite antiseizure therapy. The event’s pattern also guides medication selection. Canadian guidance identifies carbamazepine, lamotrigine, or levetiracetam as first-line choices for focal seizures. For generalized tonic-clonic seizures, options include valproic acid unless contraindicated, levetiracetam, or lamotrigine. The prescriber weighs seizure type against tolerability, comorbidities, pregnancy considerations, and interaction risk. A brief...