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Lapatinib Dosage

Applies to the following strength(s): 250 mg

The information at is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for Breast Cancer

HER2 Positive Metastatic Breast Cancer:
Initial dose: 1250 mg (5 tablets) orally once daily on days 1 through 21 continuously in combination with capecitabine

If a daily dose is missed, the patient should not double the dose the next day.

Treatment should be continued until disease progression or unacceptable toxicity occurs.

Hormone Receptor Positive, HER2 Positive Metastatic Breast Cancer:
Recommended dose: 1,500 mg orally once daily continuously in combination with letrozole.

The dose of lapatinib should be once daily (6 tablets administered all at once).

For lapatinib in general:
Lapatinib should be taken at least one hour before or one hour after a meal. Lapatinib should be taken once daily. The dose of lapatinib should not be divided.

Renal Dose Adjustments

Data are not available regarding renal dose adjustments. However, renal impairment is unlikely to affect the pharmacokinetics of lapatinib given that less than 2% of an administered dose is eliminated by the kidneys.

Liver Dose Adjustments

Patients with severe hepatic impairment (Child-Pugh Class C) should have their lapatinib dose reduced. A dose reduction to 750 mg/day in patients with severe hepatic impairment is predicted to adjust the area under the curve (AUC) to the normal range and should be considered. However, there is no clinical data with this dose adjustment in patients with severe hepatic impairment.

Dose Adjustments

Cardiac Events:
Lapatinib should be discontinued in patients with a decreased left ventricular ejection fraction (LVEF) that is Grade 2 or greater by NCI Common Terminology Criteria for Adverse Events (NCI CTCAE) and in patients with an LVEF that drops below the lower limit of normal. Lapatinib with capecitabine may be restarted at a reduced dose of 1000 mg/day and lapatinib with letrozole at a reduced dose of 1250 mg/day after a minimum of two weeks if the LVEF recovers to normal and the patient is asymptomatic.

Lapatinib therapy should be interrupted for patients with diarrhea which is NCI CTCAE Grade 3 or Grade 1 or 2 with complicating features (moderate to severe abdominal cramping, nausea or vomiting of NCI CTCAE Grade 2 or greater, decreased performance status, fever, sepsis, neutropenia, frank bleeding, or dehydration). Lapatinib may be reintroduced at a lower dose (1,250 mg/day reduced to 1,000 mg/day or 1,500 mg/day reduced to 1,250 mg/day) when diarrhea resolves to Grade 1 or less. Lapatinib should be permanently discontinued in patients with diarrhea which is NCI CTCAE Grade 4.

Other Toxicities:
Discontinuation or interruption of dosing with lapatinib may be considered when patients develop greater than or equal to Grade 2 NCI CTC toxicity and can be restarted at 1250 mg/day when the toxicity improves to Grade 1 or less. If the toxicity recurs, then lapatinib should be restarted at a lower dose (1000 mg/day).


Safety and effectiveness have not been established in pediatric patients (less than 18 years of age).


There are no data on the hemodialysis or peritoneal dialysis clearance of lapatinib. Hemodialysis would not be expected to be an effective method to enhance the elimination of lapatinib.