Lapatinib
Lapatinib is a targeted therapy medication used primarily to treat HER2-positive breast cancer. It works by inhibiting the tyrosine kinase activity of both HER2 and EGFR receptors, which are proteins that can drive cancer cell growth and proliferation.
Lapatinib is an oral tyrosine kinase inhibitor used to treat HER2-positive breast cancer by blocking cancer-promoting signaling pathways.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L01EH01
- RxNorm
- 480167
- Generic
- Lapatinib
- Class
- atc-l01
- Brands
- Tykerb
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Lapatinib is indicated for the treatment of HER2-positive (ErbB2-positive) advanced or metastatic breast cancer, typically in combination with other chemotherapy agents such as capecitabine or letrozole, for patients who have progressed on prior trastuzumab-based therapy.
Lapatinib is a 4-anilinoquinazoline derivative that reversibly inhibits the intracellular tyrosine kinase domains of both EGFR (ErbB1) and HER2 (ErbB2) receptors with high affinity, blocking downstream signaling pathways involved in cell proliferation and survival.
Common side effects include diarrhea, rash, nausea, and fatigue. Lapatinib may cause serious hepatotoxicity and cardiac toxicity (QT prolongation). It should be taken on an empty stomach, at least one hour before or after food. Drug interactions are significant as lapatinib is metabolized by CYP3A enzymes.
Official drug label
WellAlly may earn a referral fee from linked resources at no extra cost to you. Editorial content is never influenced by commercial relationships.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy