Drug interactions
Lofexidine + Quinidine
Severity: Major
Lofexidine 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
Quinidine is a strong CYP2D6 inhibitor and can raise lofexidine exposure, increasing hypotension, orthostasis and bradycardia. Both drugs also prolong the QT interval, so the risk of arrhythmia is additive.
What this interaction means in plain words
Lofexidine 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.
Lofexidine belongs to Central Nervous System; Quinidine belongs to Anti Parasitic.
Why it happens
Quinidine inhibits CYP2D6-mediated metabolism of lofexidine, and both drugs prolong cardiac repolarization.
What to do
Avoid the combination if possible. If both are needed, consider lowering the lofexidine dose, monitor ECG, heart rate and blood pressure, and correct electrolytes.
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 Lofexidine
- Adagrasib + Lofexidine Major
- Alfuzosin + Lofexidine Major
- Amiodarone + Lofexidine Major
- Amisulpride + Lofexidine Major
- Anagrelide + Lofexidine Major
- Apomorphine + Lofexidine Major
Frequently asked questions
Can I take Lofexidine with Quinidine?
MediHelp rates the interaction as major. Lofexidine 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. Quinidine is a strong CYP2D6 inhibitor and can raise lofexidine exposure, increasing hypotension, orthostasis and bradycardia. Both drugs also prolong the QT interval, so the risk of arrhythmia is additive.
How serious is the interaction between Lofexidine 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 both are needed, consider lowering the lofexidine dose, monitor ECG, heart rate and blood pressure, and correct electrolytes.
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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