Carbamazepine is chemically and stereospatially related to the tricyclic antidepressants and is spatially similar to phenytoin. Carbamazepine is oxidized by hepatic microsomal enzymes to produce its active metabolite, carbamazepine 10,11-epoxide. The autoinduction process takes about 4 weeks. Carbamazepine is a central nervous system depressant with anticholinergic effects. Toxic effects of carbamazepine include seizure, coma, hypotension, and respiratory depression, gastrointestinal hypomotility.
Cardiac toxicity is uncommon in children.
Carbamazepine induces the metabolism of other anticonvulsant drugs such as phenytoin, clonazepam, primidone, valproic acid and ethosuximide. Inhibitors of hepatic microsomal enzymes such as erythromycin, clarithromycin, cimetidine, propoxyphene increase the levels of carbamazepine. The American Association of Poison Control Centers records 7,151 carbamazepine intoxication cases in 1997. By 1997, the figure rose to 14. Complications of severe poisoning include coma, respiratory depression, and seizures.