Introduction: We report 6 confirmed cases of substantial overdose with mirtazapine, a new antidepressant compound, that occurred up to January 1997 in the United States during postmarketing surveillance or in the clinical trials.
Results: In 6 patients, the mirtazapine doses ranged from 10 to 30 times the maximum recommended dose, and there were no serious adverse effects of overdose. Two patients at special risk, a 90-year-old man and a 3-year-old child, took higher-than-usual doses without serious sequelae. The 4 patients who combined other central nervous system (CNS) depressants with mirtazapine appeared to experience more CNS depression. One patient who ingested 60 mg of alprazolam had clinically significant respiratory depression in the emergency room but recovered fully within 24 hours.
Conclusion: After an overdose of substantial multiples of mirtazapine that exceed the maximum recommended daily dosage, the new antidepressant mirtazapine appears to be safe in a limited number of cases.