Drug interactions
Indinavir + Tamoxifen
Severity: Moderate
Indinavir 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
Indinavir is a CYP3A4 inhibitor and may slow tamoxifen N-demethylation, changing exposure to its metabolites. The clinical impact on breast cancer outcomes is uncertain, and tamoxifen may modestly raise indinavir levels.
What this interaction means in plain words
Indinavir 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
CYP3A4 inhibition reduces tamoxifen metabolism to N-desmethyltamoxifen.
What to do
Consider an alternative antiretroviral that does not inhibit CYP3A4. If used together, monitor clinical response and tolerability.
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 Indinavir with Tamoxifen?
MediHelp rates the interaction as moderate. Indinavir 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. Indinavir is a CYP3A4 inhibitor and may slow tamoxifen N-demethylation, changing exposure to its metabolites. The clinical impact on breast cancer outcomes is uncertain, and tamoxifen may modestly raise indinavir levels.
How serious is the interaction between Indinavir 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: Consider an alternative antiretroviral that does not inhibit CYP3A4. If used together, monitor clinical response and tolerability.
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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