Drug interactions
Lonafarnib + Loperamide
Severity: Major
Lonafarnib and Loperamide: 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 inhibits CYP3A4 and P-glycoprotein, which can raise loperamide exposure. High loperamide exposure may cause QT prolongation, serious arrhythmias and central opioid effects, particularly in children.
What this interaction means in plain words
Lonafarnib and Loperamide 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; Loperamide belongs to Gastrointestinal Tract.
Why it happens
Inhibition of CYP3A4 metabolism and P-gp efflux increases loperamide systemic exposure.
What to do
Limit loperamide to low starting doses and titrate slowly. Monitor for cardiac effects, constipation and CNS depression, and do not use in children under 2 years.
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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References
Other interactions of Loperamide
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 Loperamide?
MediHelp rates the interaction as major. Lonafarnib and Loperamide 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 inhibits CYP3A4 and P-glycoprotein, which can raise loperamide exposure. High loperamide exposure may cause QT prolongation, serious arrhythmias and central opioid effects, particularly in children.
How serious is the interaction between Lonafarnib and Loperamide?
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 loperamide to low starting doses and titrate slowly. Monitor for cardiac effects, constipation and CNS depression, and do not use in children under 2 years.
What other medicines interact with Loperamide?
MediHelp also lists interactions of Loperamide with, for example, Amiodarone, Amisulpride, Anagrelide. The full list is on the Loperamide page.
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