A 43-y-o male with a history of AIDS, atrial fibrillation, and alcohol abus
e presented to the emergency department 2 h after ingestion of 25 tablets o
f 15 mg mirtazapine (total 375 mg) with ethanol in a suicide attempt (no ot
her coingestion). Vital signs were normal except for a mild tachycardia (ra
te 112), Physical examination was unremarkable except for lethargy. Fifty g
rams of activated charcoal with sorbitol was given. Electrocardiogram showe
d sinus tachycardia, left ventricular hypertrophy, and non-specific ST-segm
ent changes. Serum mirtazapine on admission was 530 ng/mL (therapeutic leve
l 20-50 ng/mL). Overnight monitoring revealed no tachyarrythmias, and disch
arge occurred after psychiatric evaluation. It appears that ingestions of m
irtazapine approximately 10-fold of therapeutic exhibit minimal acute toxic
ity. From this and other cases in the literature exhibiting a 10-fold overd
ose, we conclude that isolated mirtazapine ingestions of this magnitude req
uire no acute intervention other than short term (about 6 h) observation.