Carbamazepine

Carbamazepine is an anticonvulsant drug, used in particular for the treatment of trigeminal neuralgia,^​ all forms of partial epilepsy, generalized tonic-clonic seizures, and simple and complex partial seizures.^​ The specific mechanism of carbamazepine is proposed as a depressant action on transmission through the nucleus ventralis anterior of the thalamus.^​ Carbamazepine, 5H-dibenz[b,f]-azepine-5-carboxamide, is an iminostilbene derivative also recognized by its common brand name, Tegretol. In the circulation, carbamazepine is approximately 70 % bound by protein.^​ The drug is metabolized to
carbamazepine-10,11-epoxide, which is pharmacologically active, and then to carbamazepine-10,
11-dihydroxide, both of which are excreted in urine. The plasma concentration of the epoxide metabolite ranges from 15 % to 48 % of the parent compound.^​ The epoxide has a shorter half-life (5-8 hours) than the parent compound (8-60 hours).^​  The epoxide and the 10,11-dihydroxide are excreted unaltered or after conjugation to glucuronic acid.

In combination with other clinical information, monitoring carbamazepine levels provides physicians with an effective tool to aid in adjusting dosage and achieving optimal therapeutic effect while avoiding both subtherapeutic and toxic drug levels.