Drug interactions
Lonafarnib + Tolterodine
Severity: Major
Lonafarnib and Tolterodine: major interaction.
Last updated Sources: US FDA label
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
Lonafarnib is a strong CYP3A inhibitor and can increase tolterodine concentrations. This raises anticholinergic adverse effects and QT risk.
What this interaction means in plain words
Lonafarnib and Tolterodine 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.
Lonafarnib belongs to Miscellaneous; Tolterodine belongs to Genitourinary.
Why it happens
CYP3A4 inhibition by lonafarnib reduces tolterodine clearance.
What to do
Limit tolterodine to 2 mg daily and monitor for anticholinergic effects and QT prolongation, or use an alternative agent.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Lonafarnib and Tolterodine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
Other interactions of Tolterodine
Other interactions of Lonafarnib
- Alfuzosin + Lonafarnib Contraindicated
- Amobarbital + Lonafarnib Contraindicated
- Apalutamide + Lonafarnib Contraindicated
- Bosentan + Lonafarnib Contraindicated
- Carbamazepine + Lonafarnib Contraindicated
- Clarithromycin + Lonafarnib Contraindicated
Frequently asked questions
Can I take Lonafarnib with Tolterodine?
MediHelp rates the interaction as major. Lonafarnib and Tolterodine 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. Lonafarnib is a strong CYP3A inhibitor and can increase tolterodine concentrations. This raises anticholinergic adverse effects and QT risk.
How serious is the interaction between Lonafarnib and Tolterodine?
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 tolterodine to 2 mg daily and monitor for anticholinergic effects and QT prolongation, or use an alternative agent.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
