Diagnostic pitfalls associated with amoxapine overdose: A case report (original) (raw)

1990, The American Journal of Emergency Medicine

Amoxapine is a second-peneration antidepressant that has been reported to cause seixures, severe acidosis, cardiac dysrhythmias, hypotension, renal failure, coma, and cardiorespiratoty arrest in polsoning exposures. This is a report of a previously normal 9-year-old child who presented with generalized tonic clonic seizures that led to an extensive workup for primary generalized epilepsy. Nothing in the patient's history or laboratow test results su99ested innestion of a toxin. It was not until 48 hours after admission, when the child admitted taking several of her mother's amoxapine tablets, that the correct dlapnosis was made. Because of the risks and the diannostlc pitfalls associated with inoestlon of amoxapine, clinicians should be mindful of the lessons tau9ht by this case. (Am J Emery Med 1990;8:335-337. 0 1990 by W.9. Saunders Company.) Antidepressants are a leading cause of death due to poison exposure in the United States.' Newer, second generation antidepressants, ie, amoxapine, a dibenzoxazepine tricyclic compound, and maprotiline, a tetracyclic compound, have been reported to cause convulsions more commonly than traditional, first generation tricyclic antidepressants (TCAS).~*' In a retrospective review of 1,3 13 cases of cyclic antidepressant ingestions, the incidence of seizures was 24.5% in the amoxapine group and 12.2% in the maprotiline group, compared with 3.0% in the TCA group (P < 0.01).2 Amoxapine-induced seizures have been reported in nonepileptic adults who were taking doses recommended for the treatment of depression.4" The risk of death secondary to amoxapine overdose may also be greater than with other cyclic antidepressants.' Although amoxapine has somewhat less anticholinergic effect than other cyclic antidepressants,8 the clinical features of amoxapine poisoning are reported to be similar to those suggested for classical TCA overdose.2,9 The diagnostic considerations are also similar. However, we report a case that illustrates the diagnostic problems and pitfalls associated with amoxapine poisoning.