Drug interactions
Quinidine + Venlafaxine
Severity: Moderate
Quinidine 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
Venlafaxine has a modest QT-prolonging effect, particularly in overdose, and quinidine adds to this. Quinidine also inhibits CYP2D6 and can raise venlafaxine levels, which increases serotonergic and noradrenergic effects.
What this interaction means in plain words
Quinidine 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.
Quinidine belongs to Anti Parasitic; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, plus quinidine CYP2D6 inhibition raising venlafaxine exposure.
What to do
Monitor ECG and blood pressure, and correct electrolyte abnormalities. Use the lowest effective venlafaxine dose, or choose an alternative antidepressant in patients with QT risk.
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 Quinidine 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 14 days on the web. No card needed.
Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Other interactions of Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take Quinidine with Venlafaxine?
MediHelp rates the interaction as moderate. Quinidine 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. Venlafaxine has a modest QT-prolonging effect, particularly in overdose, and quinidine adds to this. Quinidine also inhibits CYP2D6 and can raise venlafaxine levels, which increases serotonergic and noradrenergic effects.
How serious is the interaction between Quinidine 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: Monitor ECG and blood pressure, and correct electrolyte abnormalities. Use the lowest effective venlafaxine dose, or choose an alternative antidepressant in patients with QT risk.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine 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.
