Drug interactions
Cobicistat + Fentanyl
Severity: Major
Cobicistat and Fentanyl: 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
Cobicistat is a strong CYP3A4 inhibitor and can substantially increase fentanyl concentrations. This raises the risk of prolonged sedation and potentially fatal respiratory depression.
What this interaction means in plain words
Cobicistat and Fentanyl 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; Fentanyl belongs to Musculoskeletal.
Why it happens
Inhibition of CYP3A4-mediated fentanyl clearance increases plasma exposure.
What to do
Avoid if possible; otherwise reduce the fentanyl dose and monitor frequently for respiratory depression and sedation, including after cobicistat is stopped.
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 Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl 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 Fentanyl?
MediHelp rates the interaction as major. Cobicistat and Fentanyl 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 increase fentanyl concentrations. This raises the risk of prolonged sedation and potentially fatal respiratory depression.
How serious is the interaction between Cobicistat and Fentanyl?
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 if possible; otherwise reduce the fentanyl dose and monitor frequently for respiratory depression and sedation, including after cobicistat is stopped.
What other medicines interact with Fentanyl?
MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl page.
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