Drug interactions
Clozapine + Voriconazole
Severity: Major
Clozapine and Voriconazole: major 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
Voriconazole can raise clozapine exposure and both drugs can prolong the QT interval. This may lead to clozapine toxicity such as sedation, seizures, hypotension, and ventricular arrhythmias.
What this interaction means in plain words
Clozapine and Voriconazole 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; Voriconazole belongs to Anti Fungals.
Why it happens
Voriconazole inhibits CYP3A4 and CYP2C19 (minor clozapine pathways), and both agents have additive QT-prolonging effects.
What to do
Prefer an alternative antifungal if feasible; otherwise monitor ECG, electrolytes and clozapine levels or adverse effects, and consider reducing the clozapine 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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Other interactions of Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole 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 Voriconazole?
MediHelp rates the interaction as major. Clozapine and Voriconazole 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. Voriconazole can raise clozapine exposure and both drugs can prolong the QT interval. This may lead to clozapine toxicity such as sedation, seizures, hypotension, and ventricular arrhythmias.
How serious is the interaction between Clozapine and Voriconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer an alternative antifungal if feasible; otherwise monitor ECG, electrolytes and clozapine levels or adverse effects, and consider reducing the clozapine dose.
What other medicines interact with Voriconazole?
MediHelp also lists interactions of Voriconazole with, for example, Avanafil, Butabarbital, Carbamazepine. The full list is on the Voriconazole page.
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