Drug interactions
Clozapine + Levoketoconazole
Severity: Major
Clozapine and Levoketoconazole: 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
Levoketoconazole inhibits CYP3A4 and may raise clozapine concentrations, increasing sedation, seizure risk, hypotension and other toxicities. Levoketoconazole also prolongs the QT interval, adding to clozapine's own cardiac risk.
What this interaction means in plain words
Clozapine and Levoketoconazole 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; Levoketoconazole belongs to Endocrine.
Why it happens
CYP3A4 inhibition reducing clozapine clearance, plus additive QTc prolongation.
What to do
Avoid if possible. If used together, monitor ECG and clozapine levels, and reduce the clozapine 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 Levoketoconazole
- Alfuzosin + Levoketoconazole Contraindicated
- Alprazolam + Levoketoconazole Contraindicated
- Amiodarone + Levoketoconazole Contraindicated
- Avanafil + Levoketoconazole Contraindicated
- Cisapride + Levoketoconazole Contraindicated
- Clarithromycin + Levoketoconazole Contraindicated
Frequently asked questions
Can I take Clozapine with Levoketoconazole?
MediHelp rates the interaction as major. Clozapine and Levoketoconazole 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. Levoketoconazole inhibits CYP3A4 and may raise clozapine concentrations, increasing sedation, seizure risk, hypotension and other toxicities. Levoketoconazole also prolongs the QT interval, adding to clozapine's own cardiac risk.
How serious is the interaction between Clozapine and Levoketoconazole?
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 used together, monitor ECG and clozapine levels, and reduce the clozapine 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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