Drug interactions
Chloroquine + Hydroxychloroquine
Severity: Major
Chloroquine and Hydroxychloroquine: 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 drugs are closely related 4-aminoquinolines that can prolong the QT interval. Combining them adds to QT risk and offers no therapeutic benefit.
What this interaction means in plain words
Chloroquine and Hydroxychloroquine 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.
Chloroquine belongs to Anti Parasitic; Hydroxychloroquine belongs to Musculoskeletal.
Why it happens
Additive QT prolongation and duplicated 4-aminoquinoline toxicity.
What to do
Avoid using the two together. If unavoidable, obtain an ECG and correct potassium and magnesium.
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 Hydroxychloroquine
- Arsenic trioxide + Hydroxychloroquine Contraindicated
- Cisapride + Hydroxychloroquine Contraindicated
- Dronedarone + Hydroxychloroquine Contraindicated
- Hydroxychloroquine + Pimozide Contraindicated
- Hydroxychloroquine + Thioridazine Contraindicated
- Hydroxychloroquine + Vandetanib Contraindicated
Other interactions of Chloroquine
- Chloroquine + Cisapride Contraindicated
- Chloroquine + Dofetilide Contraindicated
- Chloroquine + Dronedarone Contraindicated
- Chloroquine + Droperidol Contraindicated
- Chloroquine + Panobinostat Contraindicated
- Chloroquine + Pimozide Contraindicated
Frequently asked questions
Can I take Chloroquine with Hydroxychloroquine?
MediHelp rates the interaction as major. Chloroquine and Hydroxychloroquine 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 drugs are closely related 4-aminoquinolines that can prolong the QT interval. Combining them adds to QT risk and offers no therapeutic benefit.
How serious is the interaction between Chloroquine and Hydroxychloroquine?
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 using the two together. If unavoidable, obtain an ECG and correct potassium and magnesium.
What other medicines interact with Hydroxychloroquine?
MediHelp also lists interactions of Hydroxychloroquine with, for example, Arsenic trioxide, Cisapride, Dronedarone. The full list is on the Hydroxychloroquine page.
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