ABSTRACT
Drugs used to treat and prevent seizures (antiepileptic drugs, AEDs) have been among the most common drugs for which TDM is performed [1,2]. Traditionally, TDM has been applied mainly to
the “older” AEDs that have been on the market in the United States and many other countries for several decades, namely carbamazepine, phenobarbital, phenytoin, primidone, and valproic acid. These older AEDs in general have narrow therapeutic ranges and significant interindividual variability in their pharmacokinetics. Somewhat surprisingly, given the long history of TDM for AEDs, the evidence that TDM actually helps clinical management is mostly retrospective and anecdotal. Only two randomized, controlled studies of AED TDM have been performed and neither showed clear clinical benefits of TDM. Both studies did show, however, that physicians often apply information from TDM incorrectly, diminishing the clinical value of TDM [3,4]. This makes education regarding TDM a priority for the future.
