Drug interactions
Clozapine + Vemurafenib
Severity: Major
Clozapine and Vemurafenib: 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
Vemurafenib can prolong the QT interval in a concentration-dependent way, and clozapine has similar effects. Together they increase the risk of torsades de pointes and other ventricular arrhythmias.
What this interaction means in plain words
Clozapine and Vemurafenib 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; Vemurafenib belongs to Oncology.
Why it happens
Additive pharmacodynamic QT prolongation.
What to do
Avoid if possible. If both are needed, check baseline and periodic ECGs, correct electrolytes, and stop or reduce therapy if the QTc becomes markedly prolonged.
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 Vemurafenib
Frequently asked questions
Can I take Clozapine with Vemurafenib?
MediHelp rates the interaction as major. Clozapine and Vemurafenib 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. Vemurafenib can prolong the QT interval in a concentration-dependent way, and clozapine has similar effects. Together they increase the risk of torsades de pointes and other ventricular arrhythmias.
How serious is the interaction between Clozapine and Vemurafenib?
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 if possible. If both are needed, check baseline and periodic ECGs, correct electrolytes, and stop or reduce therapy if the QTc becomes markedly prolonged.
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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