Drug interactions
Fluphenazine + Tetrabenazine
Severity: Major
Fluphenazine and Tetrabenazine: major interaction.
Last updated Sources: US FDA label
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
Tetrabenazine causes dose-related QT prolongation and fluphenazine can do the same, raising the risk of torsades de pointes. Both can also cause parkinsonism and sedation, and their combination may worsen movement-disorder effects.
What this interaction means in plain words
Fluphenazine and Tetrabenazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fluphenazine belongs to Central Nervous System; Tetrabenazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, along with overlapping dopamine-related adverse effects (VMAT2 inhibition plus D2 blockade).
What to do
Avoid unless clearly necessary. If used together, obtain a baseline and follow-up ECG, correct electrolytes, and monitor for parkinsonism, sedation and depression.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine Major
Other interactions of Tetrabenazine
- Dronedarone + Tetrabenazine Contraindicated
- Isocarboxazid + Tetrabenazine Contraindicated
- Linezolid + Tetrabenazine Contraindicated
- Phenelzine + Tetrabenazine Contraindicated
- Pimozide + Tetrabenazine Contraindicated
- Procarbazine + Tetrabenazine Contraindicated
Frequently asked questions
Can I take Fluphenazine with Tetrabenazine?
MediHelp rates the interaction as major. Fluphenazine and Tetrabenazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Tetrabenazine causes dose-related QT prolongation and fluphenazine can do the same, raising the risk of torsades de pointes. Both can also cause parkinsonism and sedation, and their combination may worsen movement-disorder effects.
How serious is the interaction between Fluphenazine and Tetrabenazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid unless clearly necessary. If used together, obtain a baseline and follow-up ECG, correct electrolytes, and monitor for parkinsonism, sedation and depression.
What other medicines interact with Fluphenazine?
MediHelp also lists interactions of Fluphenazine with, for example, Arsenic trioxide, Dofetilide, Ibutilide. The full list is on the Fluphenazine page.
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