Dr Haruda raised 2 important issues. Regarding monitoring of drug levels, no recommended therapeutic ranges have been established for the newer drugs. Although levels are available for such drugs as gabapentin, lamotrigine, and topiramate, no clear relationship between drug level and clinical effect (seizure reduction or toxic effects) could be established for any of these 3 drugs. It may be that therapeutic ranges will be established in the future, but I can make no recommendations at this time.
Bourgeois BFD. Therapeutic Serum Levels for New Antiepileptic Drugs—Reply. Arch Neurol. 1999;56(10):1300. doi: