Chloroquine and Ribociclib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ribociclib
Chloroquine
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Avoid coadministration of ribociclib with agents with a known potential to prolong the QT interval, as it may increase QT interval prolongation. If concomitant use cannot be avoided, monitor ECG when initiating, during concomitant use, and as necessary. When QTcF (QT interval corrected per Fridericia formula ) prolongation is more than 480 ms and less than or equal to 500 ms: For early breast cancer: Interrupt ribociclib treatment and wait until QTcF resolves to less than 480 ms, and resume at the same dose. For advanced or metastatic breast cancer: Interrupt ribociclib treatment and wait until QTcF resolves to less than 480 ms, and reduce to the next lower dose level. If QTcF more than 480 ms recurs, interrupt ribociclib treatment and wait until QTcF resolves to less than 480 ms, then resume at next lower dose level. When QTcF prolongation is more than 500 ms: Interrupt ribociclib treatment and wait until QTcF resolves to less than 480 ms, then resume at next lower dose level. If QTcF more than 500 ms recurs, discontinue ribociclib. Permanently discontinue ribociclib if QTcF interval prolongation is either more than 500 ms or more than 60 ms change from baseline and associated with any of the following: torsade's de pointes, polymorphic ventricular tachycardia, syncope, or signs/symptoms of serious arrhythmia. If dose reduction below 200 mg/day is required, discontinue ribociclib1.
Why it happens (mechanism)
Additive QT interval prolongation
Common questions
Can I take Chloroquine and Ribociclib together?
An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Chloroquine and Ribociclib interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Chloroquine or Ribociclib need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: KISQALI(R) oral tablets, ribociclib oral tablets. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2025. DailyMed
Keep reading about Ribociclib
Keep reading about Chloroquine
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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