From the Guidelines
Zyprexa (olanzapine) is generally considered less sedating than Haldol (haloperidol) at therapeutic doses, though both medications can cause sedation. When considering the management of delirium or other conditions where sedation is a concern, the choice between olanzapine and haloperidol should be based on their sedation profiles among other factors. Olanzapine tends to have a more moderate sedation profile compared to haloperidol, which is known for its higher incidence of sedation, especially when given at higher doses or via intramuscular injection 1. However, individual responses vary significantly, and both medications should be used with caution, especially in populations that are more susceptible to sedation, such as the elderly. The sedating effects of olanzapine are related to its antagonism of histamine H1 receptors, while haloperidol's sedation is primarily due to its strong dopamine D2 receptor blockade and some antihistaminic effects. If sedation is a concern, starting with lower doses of either medication and gradually titrating upward can help minimize this side effect. For olanzapine, typical starting doses are 2.5-5 mg daily, as suggested in the management of delirium symptoms 1, while haloperidol often starts at 0.5-1 mg daily for non-acute situations. Both medications should be taken as prescribed, and any significant sedation should be reported to the prescribing clinician for potential dose adjustment. It's also worth noting that olanzapine, quetiapine, and aripiprazole appear less likely to be associated with extrapyramidal side effects (EPSEs) than first-generation antipsychotics like haloperidol, which is an important consideration in the management of delirium and other conditions 1. Given the most recent and highest quality evidence, the use of olanzapine may be preferred over haloperidol when sedation is a significant concern, due to its more moderate sedation profile and lower risk of EPSEs 1.
From the Research
Sedation Comparison Between Zyprexa and Haldol
- Zyprexa (olanzapine) and Haldol (haloperidol) are both used to treat agitation, but their sedative effects can differ.
- A study published in 2018 2 found that olanzapine resulted in a greater proportion of patients adequately sedated at 15 minutes compared to haloperidol 5 mg and haloperidol 10 mg.
- Another study from 2015 3 reported that olanzapine caused sedation in 28.6% of patients, while haloperidol caused extrapyramidal symptoms in 19% of patients.
- A review of intramuscular olanzapine in 2005 4 stated that it is at least as effective as intramuscular haloperidol in treating acute agitation, with a faster onset of action.
- A comparison study from 2003 5 found that both intramuscular olanzapine and haloperidol effectively reduced agitation, but olanzapine had a more favorable extrapyramidal symptom safety profile.
Efficacy and Safety
- The 2018 study 2 also found that midazolam achieved more effective sedation than haloperidol, ziprasidone, and perhaps olanzapine.
- The 2003 study 5 reported that olanzapine-treated patients did not spontaneously report any incidences of acute dystonia, and olanzapine had a superior EPS safety profile to that of haloperidol.
- A 2000 study 6 comparing intramuscular ziprasidone with haloperidol found that ziprasidone was associated with a lower incidence of movement disorders and a reduced requirement for anticholinergic medication.
Sedation Effects
- While Haldol (haloperidol) can cause sedation, Zyprexa (olanzapine) may be less sedating in some cases, as seen in the 2015 study 3 where sedation occurred most frequently with olanzapine, but at a rate of 28.6%.
- However, the 2018 study 2 found that olanzapine resulted in a greater proportion of patients adequately sedated at 15 minutes compared to haloperidol, suggesting that olanzapine may be more sedating in certain situations.