Drug interactions
Rolapitant + Tamoxifen
Severity: Moderate
Rolapitant and Tamoxifen: moderate 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
Rolapitant is a long-acting CYP2D6 inhibitor, and tamoxifen depends on CYP2D6 to form its most active metabolite, endoxifen. Reduced activation could diminish tamoxifen efficacy, and the inhibition may persist for weeks after a single dose.
What this interaction means in plain words
Rolapitant and Tamoxifen can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Rolapitant belongs to Gastrointestinal Tract; Tamoxifen belongs to Endocrine.
Why it happens
CYP2D6 inhibition by rolapitant reduces conversion of tamoxifen to endoxifen.
What to do
Where possible, choose an antiemetic other than rolapitant for patients on tamoxifen. Be aware that the inhibition can persist for at least 28 days after dosing.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Rolapitant
- Pimozide + Rolapitant Contraindicated
- Rolapitant + Thioridazine Contraindicated
- Atomoxetine + Rolapitant Major
- Deutetrabenazine + Rolapitant Major
- Eliglustat + Rolapitant Major
- Flecainide + Rolapitant Major
Other interactions of Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
Frequently asked questions
Can I take Rolapitant with Tamoxifen?
MediHelp rates the interaction as moderate. Rolapitant and Tamoxifen can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Rolapitant is a long-acting CYP2D6 inhibitor, and tamoxifen depends on CYP2D6 to form its most active metabolite, endoxifen. Reduced activation could diminish tamoxifen efficacy, and the inhibition may persist for weeks after a single dose.
How serious is the interaction between Rolapitant and Tamoxifen?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Where possible, choose an antiemetic other than rolapitant for patients on tamoxifen. Be aware that the inhibition can persist for at least 28 days after dosing.
What other medicines interact with Rolapitant?
MediHelp also lists interactions of Rolapitant with, for example, Pimozide, Thioridazine, Atomoxetine. The full list is on the Rolapitant page.
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