Effects of intramuscular olanzapine vs. haloperidol and placebo on QTc intervals in acutely agitated patients

Prolongation of the QTc interval has been reported during treatment with oral antipsychotic agents and may be more pronounced during parenteral administration. Pooled QTc interval data from acutely agitated patients across four double-blind trials were compared. Databases included: placebo-controlled [two schizophrenia, one bipolar mania trials (n=565)]; haloperidol-controlled [two schizophrenia trials (n=482)]; geriatric placebo-controlled [1 dementia trial (n=204)]. Patients received 1-3 injections of intramuscular (IM) olanzapine (2.5-10 mg/injection), IM haloperidol (7.5 mg/injection), or IM placebo. At 2 and 24 h after IM olanzapine treatment, the mean QTc interval decreased approximately 3 ms from baseline in the placebo- and haloperidol-controlled databases. When there was a statistically significant difference between IM olanzapine and IM placebo, QTc intervals decreased during treatment with IM olanzapine and increased with IM placebo. The incidences of prolonged (endpoint >/=99th percentile of healthy adults or >/=500 ms) or lengthened (increase >/=60 ms) QTc intervals during treatment with IM olanzapine (