Drug interactions
Rifampicin + Toremifene
Severity: Major
Rifampicin 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
Rifampicin lowers toremifene concentrations, potentially reducing efficacy in breast cancer treatment.
What this interaction means in plain words
Rifampicin 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.
Rifampicin belongs to Anti Bacterial; Toremifene belongs to Endocrine.
Why it happens
Strong CYP3A4 induction by rifampicin increases toremifene clearance.
What to do
Avoid the combination. If it is unavoidable, monitor for reduced response and consider a higher toremifene dose with clinical guidance.
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 Rifampicin
- Cabotegravir + Rifampicin Contraindicated
- Delamanid + Rifampicin Contraindicated
- Doravirine + Rifampicin Contraindicated
- Ensitrelvir + Rifampicin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
- Isavuconazole + Rifampicin Contraindicated
Frequently asked questions
Can I take Rifampicin with Toremifene?
MediHelp rates the interaction as major. Rifampicin 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. Rifampicin lowers toremifene concentrations, potentially reducing efficacy in breast cancer treatment.
How serious is the interaction between Rifampicin 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 the combination. If it is unavoidable, monitor for reduced response and consider a higher toremifene dose with clinical guidance.
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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