Drug interactions
Darunavir + Tolterodine
Severity: Moderate
Darunavir and Tolterodine: 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
Darunavir, usually boosted with ritonavir or cobicistat, inhibits CYP3A4 and may raise tolterodine exposure. This could increase anticholinergic effects and QT prolongation, particularly in CYP2D6 poor metabolizers.
What this interaction means in plain words
Darunavir and Tolterodine 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.
Darunavir belongs to Anti Virals; Tolterodine belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4-mediated tolterodine metabolism.
What to do
Limit tolterodine to 1 mg twice daily when combined with potent CYP3A4 inhibitors. Monitor for anticholinergic effects and QT-related symptoms.
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 Tolterodine
Other interactions of Darunavir
- Alfuzosin + Darunavir Contraindicated
- Avanafil + Darunavir Contraindicated
- Darunavir + Dronedarone Contraindicated
- Darunavir + Eletriptan Contraindicated
- Darunavir + Ergotamine Contraindicated
- Darunavir + Flibanserin Contraindicated
Frequently asked questions
Can I take Darunavir with Tolterodine?
MediHelp rates the interaction as moderate. Darunavir and Tolterodine 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. Darunavir, usually boosted with ritonavir or cobicistat, inhibits CYP3A4 and may raise tolterodine exposure. This could increase anticholinergic effects and QT prolongation, particularly in CYP2D6 poor metabolizers.
How serious is the interaction between Darunavir and Tolterodine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit tolterodine to 1 mg twice daily when combined with potent CYP3A4 inhibitors. Monitor for anticholinergic effects and QT-related symptoms.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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