Drug interactions
Ritonavir + Toremifene
Severity: Major
Ritonavir and Toremifene: 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
Ritonavir raises toremifene concentrations, increasing the risk of dose-related QT prolongation and arrhythmia.
What this interaction means in plain words
Ritonavir and Toremifene 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.
Ritonavir belongs to Anti Virals; Toremifene belongs to Endocrine.
Why it happens
Strong CYP3A4 inhibition by ritonavir reduces toremifene metabolism.
What to do
Avoid if possible; otherwise consider interrupting toremifene during ritonavir treatment, and monitor ECG and electrolytes.
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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Other interactions of Toremifene
- Amiodarone + Toremifene Contraindicated
- Dronedarone + Toremifene Contraindicated
- Nilotinib + Toremifene Contraindicated
- Pimozide + Toremifene Contraindicated
- Quinidine + Toremifene Contraindicated
- Ribociclib + Toremifene Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Toremifene?
MediHelp rates the interaction as major. Ritonavir and Toremifene 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. Ritonavir raises toremifene concentrations, increasing the risk of dose-related QT prolongation and arrhythmia.
How serious is the interaction between Ritonavir and Toremifene?
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 consider interrupting toremifene during ritonavir treatment, and monitor ECG and electrolytes.
What other medicines interact with Toremifene?
MediHelp also lists interactions of Toremifene with, for example, Amiodarone, Dronedarone, Nilotinib. The full list is on the Toremifene page.
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