Drug interactions
Erlotinib + Fosamprenavir
Severity: Moderate
Erlotinib and Fosamprenavir: 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
Fosamprenavir is converted to amprenavir, which inhibits CYP3A4, and it is often boosted with ritonavir. Erlotinib exposure may increase, raising the risk of diarrhea and rash.
What this interaction means in plain words
Erlotinib and Fosamprenavir 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.
Why it happens
Amprenavir inhibits CYP3A4, reducing erlotinib clearance.
What to do
Monitor for erlotinib toxicity and reduce the dose in steps if severe reactions occur. Consider an alternative antiretroviral if toxicity persists.
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 Erlotinib
- Amobarbital + Erlotinib Major
- Apalutamide + Erlotinib Major
- Carbamazepine + Erlotinib Major
- Cobicistat + Erlotinib Major
- Darunavir + Erlotinib Major
- Dexlansoprazole + Erlotinib Major
Frequently asked questions
Can I take Erlotinib with Fosamprenavir?
MediHelp rates the interaction as moderate. Erlotinib and Fosamprenavir 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. Fosamprenavir is converted to amprenavir, which inhibits CYP3A4, and it is often boosted with ritonavir. Erlotinib exposure may increase, raising the risk of diarrhea and rash.
How serious is the interaction between Erlotinib and Fosamprenavir?
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 for erlotinib toxicity and reduce the dose in steps if severe reactions occur. Consider an alternative antiretroviral if toxicity persists.
What other medicines interact with Erlotinib?
MediHelp also lists interactions of Erlotinib with, for example, Amobarbital, Apalutamide, Carbamazepine. The full list is on the Erlotinib page.
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