Concerns with antiepileptic drug initiation: safety, tolerability, and efficacy.

A number of commonly used antiepileptic drugs (AEDs) produce severe adverse effects if they are introduced at their usual daily maintenance doses. Gradual slow titration of the dose often avoids these adverse effects almost entirely. Conversely, some AEDs can be started at their effective maintenance dose and perhaps even with a loading dose. Although the mechanisms of these distinctions among antiepileptic compounds are poorly understood, the phenomenon clearly has important implications for the optimal use of the drugs, especially when rapid seizure control is desired. Examples of drugs that require gradual introduction are lamotrigine, carbamazepine, topiramate, tiagabine, and zonisamide. Phenytoin, oxcarbazepine, gabapentin, valproate, and levetiracetam are examples of drugs that can be started at an effective dose.