Drug interactions
Fluphenazine + Venlafaxine
Severity: Moderate
Fluphenazine and Venlafaxine: 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
Fluphenazine is a phenothiazine that can prolong the QT interval, and venlafaxine may add to this effect. Venlafaxine may also modestly raise fluphenazine levels through weak CYP2D6 inhibition, and both can increase the risk of arrhythmia.
What this interaction means in plain words
Fluphenazine and Venlafaxine 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.
Fluphenazine belongs to Central Nervous System; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, with possible CYP2D6 inhibition by venlafaxine increasing fluphenazine exposure.
What to do
Check a baseline ECG and electrolytes, and monitor the QTc and for extrapyramidal effects. Use the lowest effective doses.
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 Fluphenazine and Venlafaxine, 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 7 days on the web. No card needed.
Other interactions of Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Other interactions of Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine Major
Frequently asked questions
Can I take Fluphenazine with Venlafaxine?
MediHelp rates the interaction as moderate. Fluphenazine and Venlafaxine 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. Fluphenazine is a phenothiazine that can prolong the QT interval, and venlafaxine may add to this effect. Venlafaxine may also modestly raise fluphenazine levels through weak CYP2D6 inhibition, and both can increase the risk of arrhythmia.
How serious is the interaction between Fluphenazine and Venlafaxine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check a baseline ECG and electrolytes, and monitor the QTc and for extrapyramidal effects. Use the lowest effective doses.
What other medicines interact with Venlafaxine?
MediHelp also lists interactions of Venlafaxine with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Venlafaxine 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.
