Drug interactions
Cobicistat + Erlotinib
Severity: Major
Cobicistat and Erlotinib: 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
Cobicistat is a strong CYP3A4 inhibitor and can substantially raise erlotinib levels. This increases the risk of rash, diarrhea and other toxicities, including interstitial lung disease.
What this interaction means in plain words
Cobicistat and Erlotinib 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.
Cobicistat belongs to Miscellaneous; Erlotinib belongs to Oncology.
Why it happens
Cobicistat inhibits CYP3A4, reducing erlotinib metabolism.
What to do
Avoid the combination where possible. If unavoidable, reduce the erlotinib dose in 50 mg steps and monitor for diarrhea, rash and respiratory symptoms.
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 Erlotinib
- Amobarbital + Erlotinib Major
- Apalutamide + Erlotinib Major
- Carbamazepine + Erlotinib Major
- Darunavir + Erlotinib Major
- Dexlansoprazole + Erlotinib Major
- Enzalutamide + Erlotinib Major
Other interactions of Cobicistat
- Alfuzosin + Cobicistat Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Cobicistat + Colchicine Contraindicated
- Cobicistat + Dronedarone Contraindicated
- Cobicistat + Eletriptan Contraindicated
- Cobicistat + Eplerenone Contraindicated
Frequently asked questions
Can I take Cobicistat with Erlotinib?
MediHelp rates the interaction as major. Cobicistat and Erlotinib 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. Cobicistat is a strong CYP3A4 inhibitor and can substantially raise erlotinib levels. This increases the risk of rash, diarrhea and other toxicities, including interstitial lung disease.
How serious is the interaction between Cobicistat and Erlotinib?
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 unavoidable, reduce the erlotinib dose in 50 mg steps and monitor for diarrhea, rash and respiratory symptoms.
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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