Clinical success with an antiepileptic drug (AED) depends primarily on its efficacy and tolerability. Clinicians also need to have a basic understanding of an AED's pharmacokinetic characteristics, particularly those affecting the potential for drug interactions such as hepatic enzyme inhibition or induction and protein-binding displacement. Successful treatment may be complicated by pharmacokinetic characteristics such as a short half-life, nonlinear kinetics, and active metabolites. Pharmacokinetic characteristics that make a drug easy to use may affect patient adherence. In general, newer AEDs such as topiramate (TPM) are simpler to use than traditional AEDs because they have more favorable pharmacokinetic characteristics and fewer drug interactions.