Drug interactions
Clozapine + Venlafaxine
Severity: Moderate
Clozapine 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
Combining venlafaxine with clozapine can increase serotonergic activity and, rarely, cause serotonin syndrome or neuroleptic malignant syndrome. Venlafaxine may also modestly raise clozapine levels through weak CYP2D6 inhibition. Seizure threshold may also be lowered by both drugs, and cardiac effects may be additive.
What this interaction means in plain words
Clozapine 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.
Clozapine belongs to Central Nervous System; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive serotonergic and dopamine-blocking effects with possible minor CYP2D6-mediated increase in clozapine exposure.
What to do
Monitor for signs of serotonin toxicity, neuroleptic malignant syndrome, sedation and seizures, especially during initiation or dose increases. Consider checking clozapine levels if toxicity is suspected.
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 Clozapine 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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Venlafaxine?
MediHelp rates the interaction as moderate. Clozapine 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. Combining venlafaxine with clozapine can increase serotonergic activity and, rarely, cause serotonin syndrome or neuroleptic malignant syndrome. Venlafaxine may also modestly raise clozapine levels through weak CYP2D6 inhibition. Seizure threshold may also be lowered by both drugs, and cardiac effects may be additive.
How serious is the interaction between Clozapine 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 for signs of serotonin toxicity, neuroleptic malignant syndrome, sedation and seizures, especially during initiation or dose increases. Consider checking clozapine levels if toxicity is suspected.
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.
