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Drug interactions

Primaquine + Quinidine

Severity: Major

Primaquine and Quinidine: major interaction.

Last updated Sources: Base de donnees publique des medicaments (France)

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

Primaquine can prolong the QT interval, so combining it with quinidine increases the risk of torsades de pointes. Hemolysis risk from primaquine in G6PD deficiency is a separate concern.

What this interaction means in plain words

Primaquine 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.

Primaquine belongs to Anti Parasitic; Quinidine belongs to Anti Parasitic.

Evidence level: Low

Why it happens

Additive pharmacodynamic QT prolongation.

What to do

Avoid the combination where possible, and monitor ECG and electrolytes if it is necessary.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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References

Frequently asked questions

Can I take Primaquine with Quinidine?

MediHelp rates the interaction as major. Primaquine 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. Primaquine can prolong the QT interval, so combining it with quinidine increases the risk of torsades de pointes. Hemolysis risk from primaquine in G6PD deficiency is a separate concern.

How serious is the interaction between Primaquine 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, and monitor ECG and electrolytes if it is necessary.

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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