Drug interactions
Finasteride + Lapatinib
Severity: Minor
Finasteride and Lapatinib: minor 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
Lapatinib weakly inhibits CYP3A4 and might slightly raise finasteride concentrations. Finasteride is well tolerated across a broad exposure range, so the effect is unlikely to be meaningful.
What this interaction means in plain words
Finasteride and Lapatinib have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Finasteride belongs to Genitourinary; Lapatinib belongs to Oncology.
Why it happens
Lapatinib inhibits CYP3A4, which may reduce the metabolic clearance of finasteride.
What to do
No adjustment is required. Monitor only for an increase in finasteride adverse effects such as sexual dysfunction.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Finasteride
- Finasteride + Levoketoconazole Moderate
- Finasteride + Nefazodone Moderate
- Finasteride + Rifampin Moderate
- Finasteride + St john's wort Moderate
- Amobarbital + Finasteride Minor
- Aprepitant + Finasteride Minor
Other interactions of Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Finasteride with Lapatinib?
MediHelp rates the interaction as minor. Finasteride and Lapatinib have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Lapatinib weakly inhibits CYP3A4 and might slightly raise finasteride concentrations. Finasteride is well tolerated across a broad exposure range, so the effect is unlikely to be meaningful.
How serious is the interaction between Finasteride and Lapatinib?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No adjustment is required. Monitor only for an increase in finasteride adverse effects such as sexual dysfunction.
What other medicines interact with Finasteride?
MediHelp also lists interactions of Finasteride with, for example, Levoketoconazole, Nefazodone, Rifampin. The full list is on the Finasteride page.
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