Drug interactions
Lonafarnib + Quinidine
Severity: Major
Lonafarnib and Quinidine: major 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 strong CYP3A inhibitor and can raise quinidine concentrations, increasing the risk of QT prolongation. Quinidine, a weak CYP3A4 inhibitor, may also raise lonafarnib levels, since it is a sensitive CYP3A substrate.
What this interaction means in plain words
Lonafarnib and Quinidine 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; Quinidine belongs to Anti Parasitic.
Why it happens
Mutual CYP3A4 inhibition, with lonafarnib reducing quinidine clearance and quinidine reducing lonafarnib clearance.
What to do
Avoid the combination if possible. If unavoidable, reduce the quinidine dose and monitor ECG, and follow labeling for lonafarnib dose adjustment.
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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Other interactions of Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
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 Quinidine?
MediHelp rates the interaction as major. Lonafarnib and Quinidine 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 raise quinidine concentrations, increasing the risk of QT prolongation. Quinidine, a weak CYP3A4 inhibitor, may also raise lonafarnib levels, since it is a sensitive CYP3A substrate.
How serious is the interaction between Lonafarnib and Quinidine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible. If unavoidable, reduce the quinidine dose and monitor ECG, and follow labeling for lonafarnib dose adjustment.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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