Drug interactions
Clozapine + Ribociclib
Severity: Major
Clozapine and Ribociclib: major interaction.
Last updated Sources: UK SmPC
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
Ribociclib prolongs the QT interval and, as a CYP3A4 inhibitor, may raise clozapine exposure. Together they increase the risk of QT prolongation, torsades de pointes and clozapine toxicity.
What this interaction means in plain words
Clozapine and Ribociclib 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.
Clozapine belongs to Central Nervous System; Ribociclib belongs to Oncology.
Why it happens
Additive QT prolongation plus CYP3A4 inhibition by ribociclib reducing clozapine clearance.
What to do
Avoid the combination where possible. If it is necessary, monitor ECG and electrolytes and watch for clozapine adverse effects, adjusting the dose.
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
- Clozapine Viatris 100 mg Orodispersible Tablets - SmPC sections 4.3/4.5 (class statement: medicines known to increase QTc interval; "caution should be exercised when clozapine is prescribed with medicines known to increase QTc interval, or causing electrolyte imbalance.") — electronic medicines compendium (UK SmPC)
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Ribociclib
- Amiodarone + Ribociclib Contraindicated
- Cisapride + Ribociclib Contraindicated
- Dofetilide + Ribociclib Contraindicated
- Dronedarone + Ribociclib Contraindicated
- Flibanserin + Ribociclib Contraindicated
- Ibutilide + Ribociclib Contraindicated
Frequently asked questions
Can I take Clozapine with Ribociclib?
MediHelp rates the interaction as major. Clozapine and Ribociclib 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. Ribociclib prolongs the QT interval and, as a CYP3A4 inhibitor, may raise clozapine exposure. Together they increase the risk of QT prolongation, torsades de pointes and clozapine toxicity.
How serious is the interaction between Clozapine and Ribociclib?
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 the combination where possible. If it is necessary, monitor ECG and electrolytes and watch for clozapine adverse effects, adjusting the dose.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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