From the Guidelines
Olanzapine generally works better than quetiapine (Seroquel) as a PRN medication for acute agitation and psychosis due to its faster onset of action and more predictable response. According to the ESMO clinical practice guidelines 1, olanzapine may offer benefit in the symptomatic management of delirium, and its administration is associated with less likelihood of extrapyramidal side effects (EPSEs) compared to first-generation antipsychotics. The suggested starting dose for olanzapine is 2.5-5 mg p.o. or s.c. stat, and it is available in oral and parenteral formulations 1. In contrast, quetiapine is available in oral formulations only and has a suggested starting dose of 25 mg (immediate release) p.o. stat. While both medications can cause sedation, quetiapine tends to have more pronounced sedative effects at lower doses, which may be beneficial for sleep disturbances. However, the choice between these medications should consider the patient's specific symptoms, medical history, potential drug interactions, and previous medication responses. Key factors to consider include:
- Onset of action: Olanzapine has a faster onset of action (15-45 minutes for oral formulations) compared to quetiapine
- Predictability of response: Olanzapine has a more predictable response compared to quetiapine
- Dosing: Olanzapine is commonly prescribed at 5-10 mg doses, while quetiapine PRN doses typically range from 25-200 mg
- Side effects: Both medications can cause sedation, but quetiapine tends to have more pronounced sedative effects at lower doses
- Patient factors: Individual patient factors, such as sensitivity to extrapyramidal side effects or previous response to medication, should be considered when choosing between olanzapine and quetiapine.
From the Research
Comparison of Olanzapine and Seroquel as PRN Medications
- Olanzapine and Seroquel (quetiapine) are both atypical antipsychotics used to manage agitation and aggression in patients with psychotic disorders 2, 3.
- Studies have shown that olanzapine is effective in reducing symptoms of aggression and agitation, with a superior tolerability profile compared to conventional antipsychotics 2, 4.
- Quetiapine has also been shown to be effective in managing acute agitation, with similar efficacy to olanzapine and haloperidol 3.
- In terms of safety, olanzapine has been associated with fewer extrapyramidal symptoms than haloperidol and risperidone, but may cause more body weight gain and increased appetite 2.
- Quetiapine has been shown to have a similar safety profile to olanzapine, with fewer extrapyramidal symptoms than haloperidol 3.
Efficacy in Acute Agitation
- A study comparing oral risperidone, olanzapine, and quetiapine to haloperidol in psychotic agitation found that all treatments were effective in reducing aggressive behavior, with no significant between-group differences 3.
- Another study found that intravenous olanzapine was effective in achieving adequate sedation within 10 minutes, with a similar time to onset of sedation as droperidol 5.
- A retrospective analysis of intravenous push olanzapine administration found that it was safe and effective in hospitalized patients, with a low rate of adverse events 6.
Safety Considerations
- Olanzapine has been associated with a risk of hypotension, bradycardia, and cardiac arrhythmias, particularly when administered intravenously 5, 6.
- Quetiapine has been shown to have a similar safety profile to olanzapine, but may cause more somnolence and dizziness 3.
- Both medications should be used with caution in patients with a history of cardiovascular disease or other medical conditions that may increase the risk of adverse events 2, 3.