Antipsychotic as a class has diverse range of toxicity. The atypical (2nd generation) antipsychotics are considered to possess less toxicologic manifestation compared to the typical (1st generation) antipsychotics - lower K channel blockade and minimum Na channel blockade properties. However, select atypical antipsychotics overdose can results in significant morbidity in addition to sedation.
Alpha-1 blockade (hypotension)
Clozapine
Olanzapine
Quetiapine
Risperidone
Ziprasidone
Antimuscarinic effect (anticholinergic toxicity)
Clozapine
Olanzapine
Quetiapine
Delayed rectifier K channel blockade (QT prolongation)
Ertindole
Ziprasidone
Bottom line: Although lethal overdose from atypical antipsychotics are rare, they can result in significant clinical toxicity when ingested alone or in combintation with other classes of medications.
