Drug interactions
Disopyramide + Quinidine
Severity: Major
Disopyramide and Quinidine: 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
Both class Ia antiarrhythmics prolong the QT interval, and combined use raises the risk of torsades de pointes and conduction block. Quinidine may also alter disopyramide concentrations via CYP3A4.
What this interaction means in plain words
Disopyramide 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.
Disopyramide belongs to Cardiovascular; Quinidine belongs to Anti Parasitic.
Why it happens
Additive sodium and potassium channel blockade causing QT prolongation and conduction slowing.
What to do
Avoid the combination; if unavoidable, monitor ECG continuously and keep potassium and magnesium within normal range.
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 Disopyramide
- Amisulpride + Disopyramide Contraindicated
- Desipramine + Disopyramide Contraindicated
- Disopyramide + Dronedarone Contraindicated
- Disopyramide + Itraconazole Contraindicated
- Disopyramide + Ketoconazole Contraindicated
- Disopyramide + Maprotiline Contraindicated
Frequently asked questions
Can I take Disopyramide with Quinidine?
MediHelp rates the interaction as major. Disopyramide 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. Both class Ia antiarrhythmics prolong the QT interval, and combined use raises the risk of torsades de pointes and conduction block. Quinidine may also alter disopyramide concentrations via CYP3A4.
How serious is the interaction between Disopyramide 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 unavoidable, monitor ECG continuously and keep potassium and magnesium within normal range.
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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