Drug interactions
Cobicistat + Darifenacin
Severity: Major
Cobicistat and Darifenacin: 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 strongly inhibits CYP3A4 and can substantially raise darifenacin levels, increasing anticholinergic adverse effects. Darifenacin labeling limits its dose with strong CYP3A4 inhibitors.
What this interaction means in plain words
Cobicistat and Darifenacin 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; Darifenacin belongs to Genitourinary.
Why it happens
Strong CYP3A4 inhibition by cobicistat reduces darifenacin metabolism.
What to do
Limit darifenacin to 7.5 mg daily and monitor for dry mouth, constipation, urinary retention and cognitive effects. Consider an alternative agent if tolerability is poor.
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 Darifenacin
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 Darifenacin?
MediHelp rates the interaction as major. Cobicistat and Darifenacin 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 strongly inhibits CYP3A4 and can substantially raise darifenacin levels, increasing anticholinergic adverse effects. Darifenacin labeling limits its dose with strong CYP3A4 inhibitors.
How serious is the interaction between Cobicistat and Darifenacin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit darifenacin to 7.5 mg daily and monitor for dry mouth, constipation, urinary retention and cognitive effects. Consider an alternative agent if tolerability is poor.
What other medicines interact with Darifenacin?
MediHelp also lists interactions of Darifenacin with, for example, Atazanavir, Bethanechol, Clarithromycin. The full list is on the Darifenacin page.
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