Cardiac Arrest – Torsades de pointes – not just droperidol – not just theoretical
Posted Oct 05 2009 10:03pm
Many antipsychotics have been associated with prolongation of the QT interval. The package insert for olanzapine (Zyprexa), a popular antipsychotic marketed by Eli Lilly and Company, notes that “in pooled studies of adults … there were no significant differences between olanzapine and placebo in the proportion of patients experiencing potentially important changes in ECG parameters, including QT.” However recently Morissette P et al. showed that, at higher blood concentrations such as may be seen in patients with renal or hepatic insufficiency or very high daily drug dosing, olanzapine has direct cardiac electrophysiologic effects that might lead to QT prolongation in patients (olanzapine prolongs cardiac repolarization by blocking the rapid component of the delayed rectifier potassium current. J Psychopharmacol 2007;21:735-741). Also note the black box warning that this drug should not be used in elderly patients with dementia-related psychosis because there are reports of increased mortality.