Tetrabenazine and Olanzapine Interaction
Drug interaction information between Tetrabenazine and Olanzapine.
Tetrabenazine and Olanzapine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Tetrabenazine and Olanzapine. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Both drugs lower dopamine activity in the brain, which can cause stiff muscles, tremors, or a dangerous fever.
What To Do
Your doctor should watch you closely for any new movement problems or signs of a serious reaction.
FDA Label Information
7.6 Neuroleptic Drugs The risk for Parkinsonism, NMS, and akathisia may be increased by concomitant use of tetrabenazine and dopamine antagonists or antipsychotics (e.g., chlorpromazine, haloperidol, olanzapine, risperidone, thioridazine, ziprasidone) [see Warnings and Precautions ( 5.4 , 5.5 , 5.6 )] .
Tetrabenazine Also Interacts With
- Deutetrabenazine major
- Valbenazine major
- Risperidone moderate
- Ziprasidone moderate
- Haloperidol moderate
Olanzapine Also Interacts With
- Fluoxetine major
- Omeprazole minor
- Warfarin minor
- Diazepam minor
- Carbamazepine minor
Frequently Asked Questions
Can I take Tetrabenazine and Olanzapine together?
This is a moderate interaction. Your doctor should watch you closely for any new movement problems or signs of a serious reaction.
How serious is the interaction between Tetrabenazine and Olanzapine?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Tetrabenazine and Olanzapine interact?
Both drugs lower dopamine activity in the brain, which can cause stiff muscles, tremors, or a dangerous fever.
Understanding the Tetrabenazine and Olanzapine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Tetrabenazine belongs to the VMAT2 Inhibitor class and Olanzapine belongs to the Atypical Antipsychotic class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Both drugs lower dopamine activity in the brain, which can cause stiff muscles, tremors, or a dangerous fever. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Tetrabenazine has 16 total documented interactions on file in this dataset, and Olanzapine has 26. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor should watch you closely for any new movement problems or signs of a serious reaction. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Tetrabenazine or Olanzapine based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.