Drug interactions
Nirmatrelvir + Voriconazole
Severity: Major
Nirmatrelvir 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
Nirmatrelvir is only given with ritonavir, and ritonavir can lower voriconazole concentrations by inducing its metabolism. Subtherapeutic voriconazole may cause failure of antifungal treatment, although voriconazole can also raise nirmatrelvir exposure.
What this interaction means in plain words
Nirmatrelvir 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.
Nirmatrelvir belongs to Anti Virals; Voriconazole belongs to Anti Fungals.
Why it happens
The ritonavir component induces CYP2C19 and other enzymes that clear voriconazole, while voriconazole inhibits CYP3A4 metabolism of nirmatrelvir.
What to do
Avoid the combination where possible; if the antiviral is essential, monitor voriconazole trough levels and clinical response for the duration of therapy and afterwards.
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 Nirmatrelvir
- Alfuzosin + Nirmatrelvir Contraindicated
- Amiodarone + Nirmatrelvir Contraindicated
- Apalutamide + Nirmatrelvir Contraindicated
- Carbamazepine + Nirmatrelvir Contraindicated
- Colchicine + Nirmatrelvir Contraindicated
- Dronedarone + Nirmatrelvir Contraindicated
Frequently asked questions
Can I take Nirmatrelvir with Voriconazole?
MediHelp rates the interaction as major. Nirmatrelvir 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. Nirmatrelvir is only given with ritonavir, and ritonavir can lower voriconazole concentrations by inducing its metabolism. Subtherapeutic voriconazole may cause failure of antifungal treatment, although voriconazole can also raise nirmatrelvir exposure.
How serious is the interaction between Nirmatrelvir 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: Avoid the combination where possible; if the antiviral is essential, monitor voriconazole trough levels and clinical response for the duration of therapy and afterwards.
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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