Drug interactions
Nelfinavir + Tolterodine
Severity: Moderate
Nelfinavir 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
Nelfinavir inhibits CYP3A4 and can raise tolterodine concentrations, particularly in CYP2D6 poor metabolizers who depend on CYP3A4. Higher levels increase anticholinergic adverse effects and carry a risk of QT prolongation.
What this interaction means in plain words
Nelfinavir 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.
Nelfinavir belongs to Anti Virals; Tolterodine belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4 by nelfinavir reduces tolterodine clearance.
What to do
Limit tolterodine to a lower dose (labeling suggests 1 mg twice daily with potent CYP3A4 inhibitors). Monitor for anticholinergic effects and QT-risk factors.
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 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 Nelfinavir with Tolterodine?
MediHelp rates the interaction as moderate. Nelfinavir 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. Nelfinavir inhibits CYP3A4 and can raise tolterodine concentrations, particularly in CYP2D6 poor metabolizers who depend on CYP3A4. Higher levels increase anticholinergic adverse effects and carry a risk of QT prolongation.
How serious is the interaction between Nelfinavir 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 a lower dose (labeling suggests 1 mg twice daily with potent CYP3A4 inhibitors). Monitor for anticholinergic effects and QT-risk factors.
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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