Drug interactions
Perphenazine + Venlafaxine
Severity: Moderate
Perphenazine 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
Perphenazine is a phenothiazine with QT-prolonging potential, and venlafaxine may add to this. Venlafaxine weakly inhibits CYP2D6, which may increase perphenazine exposure and the risk of adverse effects and arrhythmia.
What this interaction means in plain words
Perphenazine 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.
Perphenazine belongs to Central Nervous System; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, with CYP2D6 inhibition by venlafaxine raising perphenazine levels.
What to do
Obtain a baseline ECG and electrolytes, and monitor the QTc and for extrapyramidal or sedative effects. Reduce the perphenazine dose if adverse effects emerge.
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 Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Other interactions of Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Frequently asked questions
Can I take Perphenazine with Venlafaxine?
MediHelp rates the interaction as moderate. Perphenazine 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. Perphenazine is a phenothiazine with QT-prolonging potential, and venlafaxine may add to this. Venlafaxine weakly inhibits CYP2D6, which may increase perphenazine exposure and the risk of adverse effects and arrhythmia.
How serious is the interaction between Perphenazine 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: Obtain a baseline ECG and electrolytes, and monitor the QTc and for extrapyramidal or sedative effects. Reduce the perphenazine dose if adverse effects emerge.
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.
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