Drug interactions
Lonafarnib + Zafirlukast
Severity: Moderate
Lonafarnib and Zafirlukast: 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
Lonafarnib is a sensitive CYP3A substrate, and its exposure increases with CYP3A inhibitors. Zafirlukast is a weak CYP3A4 inhibitor, so a modest rise in lonafarnib levels is possible, with greater risk of GI toxicity and possible QT concerns.
What this interaction means in plain words
Lonafarnib and Zafirlukast 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.
Lonafarnib belongs to Miscellaneous; Zafirlukast belongs to Respiratory.
Why it happens
Weak CYP3A4 inhibition by zafirlukast may reduce lonafarnib metabolism.
What to do
Continue lonafarnib at the current dose and monitor for adverse effects, palpitations or syncope; consider an alternative such as montelukast.
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 Zafirlukast
- Pimozide + Zafirlukast Contraindicated
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
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 Zafirlukast?
MediHelp rates the interaction as moderate. Lonafarnib and Zafirlukast 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. Lonafarnib is a sensitive CYP3A substrate, and its exposure increases with CYP3A inhibitors. Zafirlukast is a weak CYP3A4 inhibitor, so a modest rise in lonafarnib levels is possible, with greater risk of GI toxicity and possible QT concerns.
How serious is the interaction between Lonafarnib and Zafirlukast?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Continue lonafarnib at the current dose and monitor for adverse effects, palpitations or syncope; consider an alternative such as montelukast.
What other medicines interact with Zafirlukast?
MediHelp also lists interactions of Zafirlukast with, for example, Pimozide, Lomitapide, Nilotinib. The full list is on the Zafirlukast page.
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