Drug interactions
Olanzapine + Quetiapine
Severity: Moderate
Olanzapine and Quetiapine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both antipsychotics can prolong the QT interval modestly, and together they add sedation, orthostatic hypotension and metabolic effects. Dual antipsychotic therapy offers uncertain benefit.
What this interaction means in plain words
Olanzapine and Quetiapine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Olanzapine belongs to Central Nervous System; Quetiapine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and additive receptor-mediated sedation and hypotension.
What to do
Avoid duplicate antipsychotic therapy where possible. If combined, monitor ECG, electrolytes, sedation and metabolic parameters.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Olanzapine
Other interactions of Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Frequently asked questions
Can I take Olanzapine with Quetiapine?
MediHelp rates the interaction as moderate. Olanzapine and Quetiapine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both antipsychotics can prolong the QT interval modestly, and together they add sedation, orthostatic hypotension and metabolic effects. Dual antipsychotic therapy offers uncertain benefit.
How serious is the interaction between Olanzapine and Quetiapine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid duplicate antipsychotic therapy where possible. If combined, monitor ECG, electrolytes, sedation and metabolic parameters.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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