Drug interactions
Darifenacin + Nelfinavir
Severity: Major
Darifenacin and Nelfinavir: 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
Nelfinavir inhibits CYP3A4 and can increase darifenacin exposure, raising the risk of anticholinergic adverse effects. Darifenacin is a weak CYP3A4 inhibitor and is unlikely to matter clinically for nelfinavir.
What this interaction means in plain words
Darifenacin and Nelfinavir 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.
Darifenacin belongs to Genitourinary; Nelfinavir belongs to Anti Virals.
Why it happens
Nelfinavir inhibits CYP3A4-mediated darifenacin metabolism.
What to do
Limit the darifenacin dose to 7.5 mg daily with potent CYP3A4 inhibitors, as labeled, and monitor for dry mouth, constipation, urinary retention, and QT-related 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 Darifenacin
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Darifenacin with Nelfinavir?
MediHelp rates the interaction as major. Darifenacin and Nelfinavir 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. Nelfinavir inhibits CYP3A4 and can increase darifenacin exposure, raising the risk of anticholinergic adverse effects. Darifenacin is a weak CYP3A4 inhibitor and is unlikely to matter clinically for nelfinavir.
How serious is the interaction between Darifenacin and Nelfinavir?
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 the darifenacin dose to 7.5 mg daily with potent CYP3A4 inhibitors, as labeled, and monitor for dry mouth, constipation, urinary retention, and QT-related symptoms.
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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