Drug interactions
Atazanavir + Tolterodine
Severity: Moderate
Atazanavir 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
Atazanavir inhibits CYP3A4 and may raise tolterodine concentrations, particularly in patients who are poor CYP2D6 metabolizers and rely on CYP3A4 for clearance. This can increase anticholinergic effects and QT prolongation risk.
What this interaction means in plain words
Atazanavir 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.
Atazanavir 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 during use of potent CYP3A4 inhibitors, in line with labeling. 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 Atazanavir
- Alfuzosin + Atazanavir Contraindicated
- Atazanavir + Avanafil Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Atazanavir + Eletriptan Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Atazanavir + Ergotamine Contraindicated
Frequently asked questions
Can I take Atazanavir with Tolterodine?
MediHelp rates the interaction as moderate. Atazanavir 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. Atazanavir inhibits CYP3A4 and may raise tolterodine concentrations, particularly in patients who are poor CYP2D6 metabolizers and rely on CYP3A4 for clearance. This can increase anticholinergic effects and QT prolongation risk.
How serious is the interaction between Atazanavir 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 during use of potent CYP3A4 inhibitors, in line with labeling. 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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