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Drug

Lapatinib

Common brand names:

Tykerb

Pronounced

"la-PA-ti-nib"

Uses

Lapatinib is used to treat breast cancer. It works by slowing or stopping the growth of cancer cells.

Warning

Rarely, people taking lapatinib have developed serious (possibly fatal) liver problems. Your doctor will perform liver function tests before and during treatment to monitor for this side effect. Keep all medical/lab appointments. Tell your doctor right away if you develop symptoms of liver disease such as nausea that doesn't stop, stomach/abdominal pain, dark urine, or yellowing eyes/skin. Do not restart this medication if you have previously stopped taking it due to liver problems.

How to Use This Medication

Read the Patient Information Leaflet if available from your pharmacist before you start using lapatinib and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth 1 hour before or 1 hour after a meal as directed by your doctor, usually once daily. It is important that you do not take this medication more than once daily.

The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Do not increase your dose or take this medication more often than prescribed. Your condition will not improve any faster, and the risk of serious side effects may be increased.

Avoid eating grapefruit or drinking grapefruit juice while using this medication unless your doctor or pharmacist says you may do so safely. Grapefruit can increase the chance of side effects with this medicine. Ask your doctor or pharmacist for more details.

Since this drug can be absorbed through the skin and lungs, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

Follow your doctor's instructions on how to correctly take capecitabine or letrozole with lapatinib.

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Drug information is selected from data included with permission and copyrighted by First DataBank, Inc. This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your healthcare professional. Always seek the advice of your healthcare professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your healthcare professional. This information does not contain any assurances that this product is safe, effective or appropriate for you.

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Information expires December 2025.