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Drug interactions

Posaconazole + Ribociclib

Severity: Major

Posaconazole and Ribociclib: 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

Posaconazole is a strong CYP3A4 inhibitor that increases ribociclib exposure, and both drugs prolong the QT interval. This raises the risk of torsades de pointes and ribociclib toxicity such as neutropenia and hepatotoxicity.

What this interaction means in plain words

Posaconazole and Ribociclib 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.

Posaconazole belongs to Anti Fungals; Ribociclib belongs to Oncology.

Evidence level: Moderate

Why it happens

CYP3A4 inhibition raising ribociclib exposure plus additive QT prolongation.

What to do

Avoid if possible; otherwise reduce the ribociclib dose per labeling and monitor ECG, electrolytes and blood counts.

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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Frequently asked questions

Can I take Posaconazole with Ribociclib?

MediHelp rates the interaction as major. Posaconazole and Ribociclib 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. Posaconazole is a strong CYP3A4 inhibitor that increases ribociclib exposure, and both drugs prolong the QT interval. This raises the risk of torsades de pointes and ribociclib toxicity such as neutropenia and hepatotoxicity.

How serious is the interaction between Posaconazole and Ribociclib?

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 if possible; otherwise reduce the ribociclib dose per labeling and monitor ECG, electrolytes and blood counts.

What other medicines interact with Posaconazole?

MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.

Full monographs, dosing and an interaction checker in the MediHelp app

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