Clinical information
Common uses
- advanced HER2-positive breast cancer (with capecitabine)
- hormone-positive metastatic breast cancer (with letrozole)
Common side effects
- diarrhoea
- sore red palms and soles
- feeling sick
- rash
- tiredness
Cautions
- can cause severe, sometimes fatal, liver damage
- can weaken the heart's pumping — heart checks needed
- can cause lung inflammation — report breathing problems
- can harm an unborn baby — use contraception
Interactions
- strong CYP3A4 inhibitor medicines (avoid)
- strong CYP3A4 inducer medicines (avoid)
- raises levels of drugs broken down by CYP3A4, CYP2C8 or P-gp
Pregnancy: avoid — can harm an unborn baby
Reference information, not medical advice — always follow your doctor or pharmacist. Source: DailyMed, dailymed.nlm.nih.gov, lapatinib (Tykerb) label, setid eee37f88-ec6a-4c30-b8aa-e2c71f93088c (accessed 2026-08-16)