Drug interactions
Olanzapine + Perphenazine
Severity: Moderate
Olanzapine and Perphenazine: 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
Using two antipsychotics together adds to dopamine blockade, raising the likelihood of extrapyramidal symptoms and, rarely, neuroleptic malignant syndrome. Sedation is also additive, and both agents can modestly prolong the QT interval.
What this interaction means in plain words
Olanzapine and Perphenazine 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; Perphenazine belongs to Central Nervous System.
Why it happens
Additive dopamine D2 receptor antagonism, sedative antihistaminic effects and QT-prolonging potassium channel effects.
What to do
Use the lowest effective doses and review the need for dual antipsychotic therapy. Monitor for movement disorders, sedation and rigidity or hyperthermia, and obtain an ECG if other QT risk factors are present.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Olanzapine and Perphenazine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Other interactions of Olanzapine
Frequently asked questions
Can I take Olanzapine with Perphenazine?
MediHelp rates the interaction as moderate. Olanzapine and Perphenazine 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. Using two antipsychotics together adds to dopamine blockade, raising the likelihood of extrapyramidal symptoms and, rarely, neuroleptic malignant syndrome. Sedation is also additive, and both agents can modestly prolong the QT interval.
How serious is the interaction between Olanzapine and Perphenazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective doses and review the need for dual antipsychotic therapy. Monitor for movement disorders, sedation and rigidity or hyperthermia, and obtain an ECG if other QT risk factors are present.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
