Drug interactions
Clozapine + Olanzapine
Severity: Moderate
Clozapine and Olanzapine: 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 are atypical antipsychotics with metabolic, sedative and anticholinergic effects, and combined use increases these burdens. QT prolongation is modest for each, but combined use may add to risk, and seizure risk and weight gain can rise.
What this interaction means in plain words
Clozapine and Olanzapine 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.
Clozapine belongs to Central Nervous System; Olanzapine belongs to Central Nervous System.
Why it happens
Additive pharmacodynamic effects including receptor blockade, sedation, metabolic effects and mild QT prolongation.
What to do
Monitor weight, glucose, lipids, sedation and ECG if both are used. Avoid routine antipsychotic polypharmacy unless clearly justified.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Olanzapine
Frequently asked questions
Can I take Clozapine with Olanzapine?
MediHelp rates the interaction as moderate. Clozapine and Olanzapine 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 are atypical antipsychotics with metabolic, sedative and anticholinergic effects, and combined use increases these burdens. QT prolongation is modest for each, but combined use may add to risk, and seizure risk and weight gain can rise.
How serious is the interaction between Clozapine and Olanzapine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor weight, glucose, lipids, sedation and ECG if both are used. Avoid routine antipsychotic polypharmacy unless clearly justified.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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