The role of new antiepileptic drugs.

For many years, epileptologists had few choices for treating seizures. Within the past 20 years several "new generation" antiepileptic drugs (AEDs) were introduced. The most recent additions include oxcarbazepine, levetiracetam, and zonisamide. New agents have been shown in clinical trials to offer similar efficacy compared with older, more established AEDs, but the new agents offer important improvements in safety. Although clinical trials to specifically measure the efficacy of the new AEDs in treating idiopathic generalized epilepsy are rare, the new agents have demonstrated efficacy in treating generalized tonic-clonic convulsions. Data for treatment of Lennox-Gastaut syndrome indicate a clear effect with lamotrigine or topiramate and possibly some effect with zonisamide and levetiracetam. Studies of juvenile myoclonic epilepsy and absence seizures suggest that zonisamide, lamotrigine, topiramate, and levetiracetam may be effective. Each of the new AEDs is effective in controlling partial seizures. These agents may also be appropriate choices for newly diagnosed patients or those whose conditions are refractory to treatment. In clinical trials, patients who are refractory to treatment are often given escalated doses to gain effect, but higher doses also result in more adverse events and higher withdrawal rates. Generally, the higher the dose, the greater the odds of withdrawal, with the exception of levetiracetam, which is not associated with increased withdrawal rates at high doses. Newly diagnosed patients are likely to be controlled with the first therapy given to them. It is therefore important to select an agent with the best safety, efficacy, and tolerability profile possible.