Initial treatment of epilepsy: special issues in treating the elderly

The incidence of new-onset epilepsy is higher among the elderly, the most rapidly growing segment of the population, than in any other age group. New-onset seizures in elderly patients are typically cryptogenic or symptomatic partial seizures that require long-term treatment. Because seizures in the elderly are often readily controlled, considerations of tolerability and safety, including pharmacokinetics and the potential for drug interactions, may be as important as efficacy in the selection of an antiepileptic drug (AED). The newer AEDs introduced during the past decade offer advantages in this respect over older agents. Phenytoin is the most widely used AED in the United States, but its hepatic metabolism and associated enzyme induction, as well as its nonlinear pharmacokinetics, are particular disadvantages for elderly patients. Because of their potential effects on cognitive function, sedating AEDs such as phenobarbital and primidone have little place in the treatment of new-onset seizures in elderly patients. Carbamazepine also is an enzyme-inducing agent with significant potential for drug interactions. Among the newer AEDs, gabapentin and levetiracetam have good safety and cognitive effect profiles and do not interact with other drugs, and lamotrigine offers many of the same benefits. Oxcarbazepine has better tolerability than carbamazepine, and topiramate and zonisamide, although they have more cognitive side effects than the other new AEDs, can be considered for some elderly patients. Forthcoming data from the Veterans Affairs Cooperative Trial 428, as well as recent guidelines from the American Academy of Neurology and the American Epilepsy Society, are likely to provide support for the use of selected second-generation AEDs as first-line agents for the treatment of epilepsy in elderly patients.