Drug interactions
Lorcaserin + Tamoxifen
Severity: Moderate
Lorcaserin 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
Lorcaserin was reported to inhibit CYP2D6, which could reduce conversion of tamoxifen to endoxifen. Its clinical impact on breast cancer outcomes has not been established, and lorcaserin has been withdrawn from many markets.
What this interaction means in plain words
Lorcaserin 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.
Why it happens
Lorcaserin inhibits CYP2D6, reducing endoxifen formation.
What to do
Avoid the combination where possible and choose a different weight management option.
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 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 Lorcaserin with Tamoxifen?
MediHelp rates the interaction as moderate. Lorcaserin 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. Lorcaserin was reported to inhibit CYP2D6, which could reduce conversion of tamoxifen to endoxifen. Its clinical impact on breast cancer outcomes has not been established, and lorcaserin has been withdrawn from many markets.
How serious is the interaction between Lorcaserin 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: Avoid the combination where possible and choose a different weight management option.
What other medicines interact with Tamoxifen?
MediHelp also lists interactions of Tamoxifen with, for example, Amiodarone, Anastrozole, Bupropion. The full list is on the Tamoxifen page.
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