Metabolism of Drugs Used in the Therapy of Seizures: An Analytical Point of View. Part 1

Background: Seizures are aetiologically and clinically heterogeneous neurological disorders that are currently treated using a wide array of drugs, belonging to equally heterogeneous chemical classes. Some of them are known as “antiepileptic drugs” (AEDs), due to their main field of use, while others (such as benzodiazepines) are frequently used for other conditions as well as for seizures. Due to their different chemical properties and mechanisms of activity, the metabolic characteristics of anti-seizure drugs can vary widely, also producing big differences in terms of safety, efficacy and therapeutic suitability. Methods: Scopus and PubMed databases were searched for the most significant papers centered on metabolism and analysis of the following antiepileptics: carbamazepine, oxcarbazepine, lamotrigine, phenytoin, ethosuximide, gabapentin, vigabatrin, topiramate, levetiracetam and valproic acid. Results: The most important studies on the metabolic characteristics of several AEDs are reported and briefly discussed in this review; moreover, the analytical methods used to determine biological levels of these drugs during therapy are also described and commented upon, and their main characteristics highlighted. Other AEDs, and notes on polypharmacy, will be included in the second part of this series.