Drug interactions
Lorlatinib + Quinidine
Severity: Major
Lorlatinib and Quinidine: major interaction.
Last updated Sources: UK SmPC
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
Lorlatinib induces CYP3A4 and may lower quinidine concentrations, reducing antiarrhythmic efficacy. Loss of effect could cause arrhythmia recurrence, and quinidine exposure can fall unpredictably.
What this interaction means in plain words
Lorlatinib 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.
Lorlatinib belongs to Oncology; Quinidine belongs to Anti Parasitic.
Why it happens
Lorlatinib induction of CYP3A4 increases quinidine metabolism.
What to do
Avoid the combination where possible. If unavoidable, monitor quinidine concentrations and ECG and adjust the quinidine dose.
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 Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine Contraindicated
Other interactions of Lorlatinib
- Amobarbital + Lorlatinib Contraindicated
- Apalutamide + Lorlatinib Contraindicated
- Butabarbital + Lorlatinib Contraindicated
- Carbamazepine + Lorlatinib Contraindicated
- Enzalutamide + Lorlatinib Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
Frequently asked questions
Can I take Lorlatinib with Quinidine?
MediHelp rates the interaction as major. Lorlatinib 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. Lorlatinib induces CYP3A4 and may lower quinidine concentrations, reducing antiarrhythmic efficacy. Loss of effect could cause arrhythmia recurrence, and quinidine exposure can fall unpredictably.
How serious is the interaction between Lorlatinib 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 where possible. If unavoidable, monitor quinidine concentrations and ECG and adjust the quinidine dose.
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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