Safety of Mirtazapine in Overdose

Introduction: We report 6 confirmed cases ofsubstantial overdose with mirtazapine, a new antidepressantcompound, that occurred up to January 1997 in the United Statesduring postmarketing surveillance or in the clinical trials.

Results: In 6 patients, the mirtazapine dosesranged from 10 to 30 times the maximum recommended dose, andthere were no serious adverse effects of overdose. Two patientsat special risk, a 90year-old man and a 3-year-old child, tookhigher-than-usual doses without serious sequelae. The 4 patientswho combined other central nervous system (CNS) depressants withmirtazapine appeared to experience more CNS depression. Onepatient who ingested 60 mg of alprazolam had clinicallysignificant respiratory depression in the emergency room butrecovered fully within 24 hours.

Conclusion: After an overdose of substantialmultiples of mirtazapine that exceed the maximum recommendeddaily dosage, the new antidepressant mirtazapine appears to besafe in a limited number of cases.