Drug interactions
Tamoxifen + Voriconazole
Severity: Moderate
Tamoxifen and Voriconazole: moderate 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
Tamoxifen is activated to endoxifen mainly via CYP2D6 and CYP3A4, and voriconazole inhibits CYP3A4 and CYP2C9. This may change tamoxifen metabolite profiles, with uncertain effect on efficacy. Both drugs can also prolong QT.
What this interaction means in plain words
Tamoxifen and Voriconazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Tamoxifen belongs to Endocrine; Voriconazole belongs to Anti Fungals.
Why it happens
Voriconazole inhibits CYP3A4/2C9 metabolism of tamoxifen; additive QT prolongation is also possible.
What to do
Monitor ECG in patients with QT risk factors and review the need for an azole in long-term tamoxifen therapy. Consider a shorter antifungal course or an alternative agent.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
Frequently asked questions
Can I take Tamoxifen with Voriconazole?
MediHelp rates the interaction as moderate. Tamoxifen and Voriconazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Tamoxifen is activated to endoxifen mainly via CYP2D6 and CYP3A4, and voriconazole inhibits CYP3A4 and CYP2C9. This may change tamoxifen metabolite profiles, with uncertain effect on efficacy. Both drugs can also prolong QT.
How serious is the interaction between Tamoxifen and Voriconazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG in patients with QT risk factors and review the need for an azole in long-term tamoxifen therapy. Consider a shorter antifungal course or an alternative agent.
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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