Drugs A - Z

Lapatinib Oral tablet

It targets specific enzymes within cancer cells and stops the cancer cells from growing

Generic Name: lapatinib

Brand Names: Tykerb

There is an FDA Alert for this drug. Click here to view it.

  • Potentially severe or fatal hepatotoxicity observed. Causality of the deaths uncertain. (See Hepatic Toxicity under Cautions.)

What is this medicine?

LAPATINIB (la PA ti nib) is a chemotherapy drug. It targets specific enzymes within cancer cells and stops the cancer cells from growing. This medicine is used to treat some advanced breast cancers. It is often used along with other cancer treatments.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • heart disease
  • heart rhythm problems (irregular heartbeat)
  • high blood pressure
  • history of low levels of potassium or magnesium
  • liver disease
  • an unusual reaction to lapatinib, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. Take this medicine on an empty stomach, at least 1 hour before or after a meal. Do not take with food. Follow the directions on the prescription label. Do not take your medicine more often than directed. Do not stop taking except on your doctor's advice.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed. This medicine is not approved for use in children.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

Do not take this medicine with any of the following:
  • grapefruit or grapefruit juice

This medicine may also interact with the following medications:

  • antiviral medicines for HIV or AIDS
  • cisapride
  • clarithromycin
  • cyclosporine
  • daunorubicin
  • dexamethasone
  • diltiazem
  • doxorubicin
  • erythromycin
  • medicines for depression, anxiety or psychotic disturbances
  • medicines for fungal infections itraconazole, ketoconazole
  • medicines for irregular heart beat
  • medicines for seizures like carbamazepine, phenobarbital, phenytoin
  • rifabutin, rifampin, rifapentine
  • St. John's Wort or other herbal supplements
  • stomach acid blockers like cimetidine, famotidine, ranitidine, or omeprazole
  • telithromycin
  • verapamil

What should I watch for while using this medicine?

Visit your doctor for checks on your progress. You will need to have regular blood tests while on this medicine.

Report any new symptoms promptly. Let your doctor know if you have any change in bowel patterns, nausea, loss of appetite, or vomiting, as these side effects may cause dehydration. If you have shortness of breath, contact your doctor. Possible serious side effects include heart or lung problems.

Do not become pregnant while taking this medicine. Women should inform their doctor if they wish to become pregnant or think they might be pregnant. There is a potential for serious side effects to an unborn child. Talk to your health care professional or pharmacist for more information. Do not breast-feed an infant while taking this medicine.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
  • allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
  • breathing problems
  • chest pain
  • cough that does not go away
  • dizziness
  • feeling faint or lightheaded, falls
  • fever or chills, sore throat
  • palpitations
  • severe or persistent diarrhea
  • swelling of feet, legs
  • unusual bleeding, bruising
  • vomiting
  • yellowing of the eyes or skin

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • decreased appetite
  • diarrhea
  • dry skin
  • heartburn
  • mouth sores
  • nausea
  • red, numb, swollen, or painful hands or feet
  • stomach upset
  • tired

Last Updated: June 25, 2013
Licensed from
The Healthline Site, its content, such as text, graphics, images, search results, HealthMaps, Trust Marks, and other material contained on the Healthline Site ("Content"), its services, and any information or material posted on the Healthline Site by third parties are provided for informational purposes only. None of the foregoing is a substitute for professional medical advice, examination, diagnosis, or treatment. Always seek the advice of a physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on the Healthline Site. If you think you may have a medical emergency, call your doctor or 911 immediately. Please read the Terms of Service for more information regarding use of the Healthline Site.