Drug interactions
Losartan + Tucatinib
Severity: Moderate
Losartan and Tucatinib: 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
Tucatinib inhibits CYP3A and may raise losartan parent drug exposure while reducing active metabolite formation. Losartan is not a significant CYP2C8 inhibitor, so tucatinib levels are not expected to rise meaningfully.
What this interaction means in plain words
Losartan and Tucatinib 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.
Losartan belongs to Cardiovascular; Tucatinib belongs to Oncology.
Why it happens
Tucatinib inhibition of CYP3A4 alters losartan metabolism.
What to do
Monitor blood pressure and adjust the losartan dose if hypotension or reduced effect appears.
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 Losartan
- Aliskiren + Losartan Contraindicated
- Losartan + Sparsentan Contraindicated
- Amifostine + Losartan Major
- Amiloride + Losartan Major
- Amlodipine-benazepril + Losartan Major
- Amlodipine-hydrochlorothiazide-valsartan + Losartan Major
Other interactions of Tucatinib
- Cisapride + Tucatinib Contraindicated
- Eletriptan + Tucatinib Contraindicated
- Ergotamine + Tucatinib Contraindicated
- Flibanserin + Tucatinib Contraindicated
- Ranolazine + Tucatinib Contraindicated
- Amobarbital + Tucatinib Major
Frequently asked questions
Can I take Losartan with Tucatinib?
MediHelp rates the interaction as moderate. Losartan and Tucatinib 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. Tucatinib inhibits CYP3A and may raise losartan parent drug exposure while reducing active metabolite formation. Losartan is not a significant CYP2C8 inhibitor, so tucatinib levels are not expected to rise meaningfully.
How serious is the interaction between Losartan and Tucatinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure and adjust the losartan dose if hypotension or reduced effect appears.
What other medicines interact with Losartan?
MediHelp also lists interactions of Losartan with, for example, Aliskiren, Sparsentan, Amifostine. The full list is on the Losartan page.
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