Oxcarbazepine

OXCARBAZEPINE

Oxcarbazepine is closely related to carbamazepine and is useful in the same seizure types, but it may have an improved toxicity pro-file. Oxcarbazepine has a half-life of only 1–2 hours. Its activity, therefore, resides almost exclusively in the 10-hydroxy metabolite (especially the S(+) enantiomer, eslicarbazepine), to which it is rapidly converted and which has a half-life similar to that of car-bamazepine, ie, 8–12 hours. The drug is mostly excreted as the glucuronide of the 10-hydroxy metabolite.

Oxcarbazepine is less potent than carbamazepine, both in ani-mal models of epilepsy and in epileptic patients; clinical doses of oxcarbazepine may need to be 50% higher than those of carbam-azepine to obtain equivalent seizure control. Some studies report fewer hypersensitivity reactions to oxcarbazepine, and cross-reac-tivity with carbamazepine does not always occur. Furthermore, the drug appears to induce hepatic enzymes to a lesser extent than carbamazepine, minimizing drug interactions. Although hypona-tremia may occur more commonly with oxcarbazepine than with carbamazepine, most adverse effects that occur with oxcarbazepine are similar in character to reactions reported with carbamazepine.