Acute carbamazepine toxicity resulting from overdose.

Four patients with an acute overdose of carbamazepine were examined with serial blood level determinations. The clinical spectrum consisted of coma, respiratory depression, seizures, myoclonus, nystagmus, hyperreflexia, hyporeflexia, delayed gastric emptying with cyclic coma, ataxia, sinus tachycardia, and atrioventricular conduction delay. Carbamazepine elimination half-lives varied from 10 to 29 hours, and in one case carbamazepine-10,11-epoxide was measured and had a half-life of 24 hours.