Drug interactions
Fosamprenavir + Voriconazole
Severity: Major
Fosamprenavir and Voriconazole: 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
Both drugs are CYP3A4 substrates and inhibitors, so levels of each may rise. Fosamprenavir (amprenavir) can also change voriconazole exposure, and the net effect is unpredictable, risking toxicity or loss of antifungal efficacy.
What this interaction means in plain words
Fosamprenavir 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.
Why it happens
Mutual interference with CYP3A4 metabolism, with possible additional effects on voriconazole clearance via CYP2C19.
What to do
Avoid the combination if possible. If used, monitor for toxicity of both drugs, check voriconazole trough levels and monitor antiretroviral response.
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 Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Frequently asked questions
Can I take Fosamprenavir with Voriconazole?
MediHelp rates the interaction as major. Fosamprenavir 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. Both drugs are CYP3A4 substrates and inhibitors, so levels of each may rise. Fosamprenavir (amprenavir) can also change voriconazole exposure, and the net effect is unpredictable, risking toxicity or loss of antifungal efficacy.
How serious is the interaction between Fosamprenavir 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 if possible. If used, monitor for toxicity of both drugs, check voriconazole trough levels and monitor antiretroviral response.
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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