Medication Information Leaflet

​What is this medication for?

Lapatinib is a targeted medication used to treat advanced breast cancer. It is normally given together with another oral medication.

How should I take/use this medication?

  • Take Lapatinib once a day at around the same time each day. Take the exact dose that the doctor tells you to.
  • Take Lapatinib on an empty stomach (at least 1 hour before or 1 hour after food).
  • Do not break or crush the tablet. Swallow the tablet whole.
    • Inform your doctor or pharmacist if you have difficulty swallowing.

What should I do if I forget to take/use this medication?

If you forget to take a dose, skip the missed dose and take your next dose at the usual time. Do not take two doses to make up for the missed dose. 

What precautions should I take?

Inform your healthcare professional if: 

  • You are allergic to this medication or any of the other ingredients of this medication
  • You are pregnant or planning to become pregnant
    • You should use effective birth control during treatment
  • You are taking any other medications, including supplements, traditional medications and herbal remedies

What are some common side-effects of this medication?

  • Diarrhea
  • Palms of the hands or soles of the feet may become dry, sore and have peeling
    • Especially if taken together with Capecitabine
  • Nausea and vomiting
  • Rash, dry skin, itch
  • Feeling tired

What are some rare but serious side-effects that I need to seek medical advice immediately?

  • Fever of 38° C or higher
  • Sores or ulcers in mouth and throat
  • Unusual bleeding, bruising or black sticky stools
  • Rapid or irregular heartbeat
  • Chest pain, cough or shortness of breath as heart issues may develop rarely
  • Unusual water retention or swelling of the hands or feet
  • Yellowing of the eyes or skin, or dark tea-coloured urine

The symptoms of a drug allergy include one or more of the following: 

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take this medication?

Avoid taking grapefruit when you are taking this medication as grapefruit may interact with Lapatinib and increases the risk of side-effects.

Avoid traditional Chinese medication (TCM) or ‘Jamu’ when you are on this medication.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How should I throw away this medication safely?

Pack Lapatinib into a bag and bring it back to the pharmacy where you received the medication from. 


If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Jan 2022


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