About lapatinib ditosylate
HER2 and EGFR tyrosine kinase inhibitor
Used for
- Used with capecitabine for advanced or metastatic HER2-positive breast cancer after prior treatment.
- Used with letrozole for hormone receptor-positive, HER2-positive metastatic breast cancer.
Usual adult dose
1,250 mg once daily with capecitabine, or 1,500 mg once daily with letrozole; take on an empty stomach.
Common side effects
- Diarrhea
- Rash
- Nausea and vomiting
- Fatigue
Important warnings
- May cause serious liver injury; liver tests are monitored.
- Can cause heart problems and reduced pumping function.
- Severe diarrhea can cause dehydration and require urgent treatment.
- May prolong the heart rhythm interval; monitoring may be needed.
Pregnancy
May harm an unborn baby. Effective contraception is recommended during treatment and for one week after the last dose.
Breastfeeding
Breastfeeding is not recommended during treatment and for one week after the last dose.
Interactions
- Strong CYP3A4 inhibitors can increase lapatinib levels; avoid or adjust treatment.
- Strong CYP3A4 inducers can reduce lapatinib levels and effectiveness.
- Avoid grapefruit and grapefruit juice.
- Lapatinib can increase levels of some medicines, including certain statins and heart-rhythm drugs.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.