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About treatment

TYKERB® (lapatinib) tablets is designed to inhibit HER2 receptors

  • HER2 is a type of protein found on normal cells as well as breast cancer cells
  • In women with HER2+ breast cancer, the breast cancer cells have too many HER2 receptors (designated as HER2+)
  • When these HER2 receptors join together, they direct cancer cells to grow and divide

TYKERB works inside cancer cells to block HER2 receptors

  • TYKERB is a small molecule that passes through the surface of cells and may help block HER2 receptor activity
  • Once inside the cell, TYKERB binds to the HER2 protein receptor inside the cell

When tested in animals and in human breast cancer cells grown outside the body, TYKERB blocked HER2 receptors and cell growth.


Getting Started

Take time to learn about TYKERB

  • Be sure you understand how to take TYKERB with letrozole according to your doctor's directions. If you have any questions, contact your doctor or nurse. This is important for fighting your cancer

Tell your doctor

Before you take TYKERB, tell your doctor if you:

  • Have heart problems
  • Have liver problems. You may need a lower dose of TYKERB
  • Have any other medical conditions
  • Are pregnant or plan to become pregnant. TYKERB can harm your unborn baby. You should not become pregnant while taking TYKERB. Tell your doctor right away if you become pregnant during treatment with TYKERB
  • Are breastfeeding or plan to breastfeed. It is not known if TYKERB passes into your breast milk. You and your doctor should decide if you will take TYKERB or breastfeed. You should not do both

Tell your doctor about the medicines

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. TYKERB may affect the way other medicines work, and other medicines may affect the way TYKERB works. Especially tell your doctor if you take:

  • Antibiotics and antifungal medicines (used to treat infections)
  • HIV medicines
  • Medicines used to treat seizures
  • Medicines used to treat heart problems or high blood pressure
  • Antidepressants
  • Medicines that reduce stomach acid (antacids)
  • St John’s wort

Talk to your doctor about side effects.

It is important to know that you may experience side effects while taking TYKERB.

Always speak with your doctor or nurse about any side effects you have while taking TYKERB.


Your Regimen

oral medicine

TYKERB is an oral medicine

  • Take 6 tablets of TYKERB all at once, one time a day, every day (unless your doctor directs otherwise)
  • You take TYKERB by mouth with a glass of water
  • Do not crush, break, or chew tablets
  • You can take TYKERB at home or wherever you happen to be—you don't need to go to the doctor’s office or clinic
  • Take TYKERB on an empty stomach (at least 1 hour before or 1 hour after a meal)
  • Do not eat or drink grapefruit products during treatment with TYKERB. Grapefruit may increase the amount of TYKERB in your blood
  • If you miss a dose of TYKERB, take your next dose at your regular time the next day. Do not take 2 doses at 1 time
  • If you take too much TYKERB, call your doctor or go to the nearest hospital emergency room right away

When taking TYKERB with letrozole:

  • Take your prescribed dose of TYKERB tablets together and at the same time every day
  • Your doctor will tell you the dose of letrozole you should take and when you should take it
  • The recommended dose of letrozole while taking TYKERB is 1 tablet, once a day
  • Take TYKERB on an empty stomach (at least 1 hour before or 1 hour after a meal)
  • You can take letrozole on an empty or full stomach
  • Continue this regimen as directed by your doctor
  • Talk to your doctor if you have any questions about your treatment or experience any side effects

Side effects

Serious Side Effects

Expand all

  • Heart problems, including decreased pumping of blood from the heart and an abnormal heartbeat
  • Signs and symptoms of an abnormal heartbeat include:
    • Feeling like your heart is pounding or racing
    • Dizziness
    • Tiredness
    • Feeling light-headed
    • Shortness of breath
  • Your doctor should check your heart function before you start taking TYKERB and during treatment

  • Liver problems can be severe and deaths have happened
  • Signs and symptoms of liver problems include:
    • Itching
    • Yellowing of your skin or the white part of your eyes
    • Dark urine
    • Pain or discomfort in the right upper stomach area
  • Your doctor should do blood tests to check your liver before you start taking TYKERB and during treatment

  • Symptoms of lung problems with TYKERB include:
    • A cough that will not go away
    • Shortness of breath

  • TYKERB may cause severe skin reactions
  • Tell your doctor right away if you develop:
    • Skin rash
    • Red skin
    • Blistering of the lips, eyes, or mouth
    • Peeling skin
    • Fever
    • Any combination of these reactions
  • Severe skin reactions can be life threatening, so your doctor may tell you to stop taking TYKERB

  • Diarrhea is common with TYKERB and may sometimes be severe
  • Severe diarrhea can cause loss of body fluid (dehydration) and some deaths have happened
  • Call your doctor right away if you have a change in bowel pattern or if you have severe diarrhea
  • Follow your doctor’s instructions for what to do to help prevent or treat diarrhea

Call your doctor right away if you have any of the signs or symptoms of the serious side effects listed.

Please see the full Prescribing Information for a full listing of the serious side effects.

When TYKERB is taken with letrozole, common side effects include:

  • Diarrhea
  • Nausea
  • Rash
  • Tiredness or weakness
  • Vomiting
  • Headache
  • Dry skin
  • Unusual hair loss or thinning
  • Itching
  • Loss of appetite
  • Nosebleeds
  • Nail disorders such as nail bed changes, nail pain, infection, and swelling of the cuticles

Novartis Oncology Patient Support Program

Support designed for patients and caregivers


  • Insurance and Medicare education to help you understand the insurance process
  • Financial assistance for eligible patients*
  • Patient Navigators who provided 1-on-1 support specific to your Novartis medicine(s)*
  • Information about independent organizations that can assist you with your day-to-day needs beyond medical care
  • Patient Support Counselors who are able to provide information in over 160 languages

*Varies by product


To learn more about what’s available, call 1-800-282-7630 or visit