Drug interactions
Itraconazole + Quetiapine
Severity: Major
Itraconazole and Quetiapine: major interaction.
Last updated Sources: US FDA label
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
Itraconazole markedly increases quetiapine exposure, which may cause excessive sedation, hypotension and QT prolongation. Both agents prolong the QT interval.
What this interaction means in plain words
Itraconazole and Quetiapine 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.
Itraconazole belongs to Anti Fungals; Quetiapine belongs to Central Nervous System.
Why it happens
Strong CYP3A4 inhibition by itraconazole reduces quetiapine clearance, with additive QT effects.
What to do
Reduce the quetiapine dose substantially during itraconazole therapy, as in labeling for strong CYP3A4 inhibitors. Monitor ECG, sedation and blood pressure, and restore the dose after stopping.
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 Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole Contraindicated
Other interactions of Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Frequently asked questions
Can I take Itraconazole with Quetiapine?
MediHelp rates the interaction as major. Itraconazole and Quetiapine 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. Itraconazole markedly increases quetiapine exposure, which may cause excessive sedation, hypotension and QT prolongation. Both agents prolong the QT interval.
How serious is the interaction between Itraconazole and Quetiapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce the quetiapine dose substantially during itraconazole therapy, as in labeling for strong CYP3A4 inhibitors. Monitor ECG, sedation and blood pressure, and restore the dose after stopping.
What other medicines interact with Itraconazole?
MediHelp also lists interactions of Itraconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Itraconazole page.
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