Drug interactions
Lapatinib + Tadalafil
Severity: Minor
Lapatinib and Tadalafil: 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 is a weak to moderate CYP3A4 inhibitor and may increase tadalafil concentrations. This could increase tadalafil adverse effects such as hypotension, headache and flushing.
What this interaction means in plain words
Lapatinib and Tadalafil 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 belongs to Oncology; Tadalafil belongs to Genitourinary.
Why it happens
Inhibition of CYP3A4-mediated tadalafil metabolism by lapatinib.
What to do
No empiric dose change is usually required. Monitor for tadalafil adverse effects and lower the dose if they occur.
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 Tadalafil
- Amyl nitrite + Tadalafil Contraindicated
- Isosorbide dinitrate + Tadalafil Contraindicated
- Isosorbide mononitrate + Tadalafil Contraindicated
- Nitroglycerin po + Tadalafil Contraindicated
- Nitroglycerin rectal + Tadalafil Contraindicated
- Nitroglycerin sublingual + Tadalafil Contraindicated
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 Lapatinib with Tadalafil?
MediHelp rates the interaction as minor. Lapatinib and Tadalafil 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 is a weak to moderate CYP3A4 inhibitor and may increase tadalafil concentrations. This could increase tadalafil adverse effects such as hypotension, headache and flushing.
How serious is the interaction between Lapatinib and Tadalafil?
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 empiric dose change is usually required. Monitor for tadalafil adverse effects and lower the dose if they occur.
What other medicines interact with Tadalafil?
MediHelp also lists interactions of Tadalafil with, for example, Amyl nitrite, Isosorbide dinitrate, Isosorbide mononitrate. The full list is on the Tadalafil page.
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