Drug interactions
Clozapine + Lopinavir
Severity: Major
Clozapine and Lopinavir: major interaction.
Last updated Sources: Health Canada product monograph
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
Both drugs can prolong the QT interval, raising the risk of ventricular arrhythmias including torsades de pointes. Lopinavir/ritonavir inhibits CYP3A4, which may also increase clozapine exposure, while ritonavir may induce other pathways, making the net effect unpredictable.
What this interaction means in plain words
Clozapine and Lopinavir 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; Lopinavir belongs to Anti Virals.
Why it happens
Additive QTc prolongation, with possible pharmacokinetic alteration of clozapine metabolism by ritonavir-boosted lopinavir.
What to do
Check baseline ECG and electrolytes and monitor QTc during therapy. Monitor clozapine levels and adverse effects, and adjust the dose as needed.
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
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 Lopinavir
- Alfuzosin + Lopinavir Contraindicated
- Avanafil + Lopinavir Contraindicated
- Cisapride + Lopinavir Contraindicated
- Dronedarone + Lopinavir Contraindicated
- Eletriptan + Lopinavir Contraindicated
- Eplerenone + Lopinavir Contraindicated
Frequently asked questions
Can I take Clozapine with Lopinavir?
MediHelp rates the interaction as major. Clozapine and Lopinavir 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. Both drugs can prolong the QT interval, raising the risk of ventricular arrhythmias including torsades de pointes. Lopinavir/ritonavir inhibits CYP3A4, which may also increase clozapine exposure, while ritonavir may induce other pathways, making the net effect unpredictable.
How serious is the interaction between Clozapine and Lopinavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check baseline ECG and electrolytes and monitor QTc during therapy. Monitor clozapine levels and adverse effects, and adjust the dose as needed.
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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