Patient Education Quick Reference Guide Diablo Valley Oncology/Hematology Medical Group Phone Number: 925-677-5041

Description Your treatment is called lapatinib (la-PA-ti-nib) or Tykerb® (TIE-curb). It is commonly used to treat breast cancer and has also been used to treat other diseases. Lapatinib is a new type of drug called a tyrosine kinase inhibitor which targets cancer cells more precisely than chemotherapy drugs.

What Do I Need to Know Before Starting Treatment?

  • Be sure to tell your healthcare provider about any prescription or over-the-counter products you are taking, including dietary supplements, vitamins, herbal medicines and homeopathic remedies.
  • Use an effective birth control method while you are being treated. Lapatinib can cause harm to a fetus, so be sure to tell your healthcare provider right away if you or your partner become pregnant.
  • Avoid breastfeeding during treatment. It is not known if lapatinib passes into breast milk.
  • Some drugs can cause sterility. Talk with your healthcare provider about your options if you want to have children in the future.
  • Do not get any immunizations or vaccinations while you are being treated without the approval of your healthcare provider.

What Do I Need to Know Before Starting Lapatinib?

  • Lapatinib can cause heart problems, such as an irregular heartbeat and congestive heart failure. This side effect may be more common in patients with a history of heart disease. Tell your healthcare provider if you have shortness of breath, heart palpitations or fatigue.
  • Lapatinib can cause diarrhea that can sometimes be severe. Please see “What Are the Possible Side Effects” in the chart below. Tell your healthcare provider if you develop severe diarrhea with lapatinib.
  • Lapatinib can cause lung problems, called interstitial lung disease or pneumonitis. Your healthcare provider will check how well your lungs are working while you are taking lapatinib and decide if you need to stop treatment.
  • Tell your healthcare provider if you have a history of liver disease. If so, your dose of lapatinib may need to be changed.
Your treatment can interact with other substances, including:
  • Drugs used to treat seizures, such as phenytoin (Dilantin®), phenobarbital or carbamazepine (Tegretol®)
  • Drugs used to treat fungal infections, such as fluconazole, ketoconazole, itraconazole and voriconazole
  • Certain antibiotics, such as rifampin, rifabutin, clarithromycin, erythromycin and troleandomycin
  • Certain antidepressants, such as nefazodone and fluvoxamine
  • Other anticancer medications, such as irinotecan
  • Grapefruit and grapefruit juice
  • St. John’s wort, ginkgo biloba, kava, grape seed, valerian, ginseng, echinacea and evening primrose oil
  • Calcium channel blockers, such as verapamil and diltiazem
  • Cimetidine (T agamet®), aprepitant and amiodarone
  • Antacids, such as Mylanta®, Tums® and Maalox® should not be taken within one hour before or after lapatinib
  • Oral corticosteroids, such as dexamethasone, prednisone and hydrocortisone
  • Drugs used to treat HIV (AIDS) infection, such as efavirenz, nevirapine, delaviridine, nelfinavir, amprenavir, ritonavir, indinavir, saquinavir and lopinivir
Please note this list is a summary and does not contain all possible drug interactions. Contact your healthcare provider if you are taking any medications that can interact with your treatment.  

Who Should Not Take This Treatment

You should not take this treatment if you are allergic to lapatinib or any components of this drug.

How Is the Treatment Given?

  • Lapatinib is taken once a day. It is important that you do not divide the dose. You should take lapatinib at least one hour before or one hour after a meal.
  • If you miss a dose of lapatinib, but remember the same day, take it as soon as you remember. If you miss a day, do not double your dose the next day. Just skip the missed dose.
  • It is important to take lapatinib exactly as prescribed. Do not stop the medicine or change the dose without talking with your healthcare provider.
  • Store lapatinib at room temperature away from children and pets. If you take too much lapatinib, contact your healthcare provider, local poison control center or emergency room right away.
  • If you are given any medicine to take at home, do not share it with others. Sharing this medication with anyone else could be harmful.

When Should I Call My Healthcare Provider?

Call your healthcare provider right away if you have any of the following symptoms:
  • Shaking chills or fever of 100.5 degrees F or higher
  • Unusual bleeding, easy bruising or pinpoint red spots on your skin
  • Vomiting that is severe or lasts several hours
  • Painful or frequent urination or blood in your urine
  • Diarrhea that causes an additional four bowel movements a day, diarrhea that lasts more than one day, diarrhea at night or diarrhea with fever, cramps or bloody stools
  • Irregular or rapid heart beat, chest pain, chest tightness or shortness of breath
  • Dizziness or feeling lightheaded
  • Inability to eat or weight loss

What Are the Possible Side Effects?

All drugs can cause side effects, but every person reacts differently to each drug. The following chart lists the possible side effects that can occur with your treatment, how to recognize and minimize symptoms and possible treatments. The side effects are grouped by how often the side effect occurs: Common (occurs in more than 25 percent of patients), Less Common (occurs in 5 to 25 percent of patients) or Rare (occurs in less than 5 percent of patients).

Side Effect

How to Minimize Side Effect

Possible Treatments

Diarrhea (Common)
  • Loose or watery stools several times a day
  • Abdominal cramping, gas and bloating
  • Eat small, frequent meals and bland foods— such as bananas, rice, applesauce and toast.
  • Avoid caffeine; alcohol; raw fruits and vegetables; raw eggs; undercooked meats; spicy, fatty and greasy foods; milk and dairy products; foods that cause gas, such as beans and other legumes; high fiber and high-fat foods; foods left un-refrigerated for more than two hours (one hour for egg dishes and cream or mayonnaise-based foods); bulk laxatives; and stool softeners.
  • Drink eight to ten glasses of clear liquids every day.
  • Your healthcare provider may prescribe medicine to help treat diarrhea.
Nausea/Vomiting (Common)
  • Feeling queasy or sick to your stomach
  • Eat small, frequent meals and bland foods— such as bananas, rice, applesauce and toast.
  • Eat food cold or at room temperature so the smell of food will not bother you.
  • Avoid fried, spicy or fatty foods.
  • Eat and drink slowly.
  • Drink plenty of liquids during the day, but to avoid bloating, drink small amounts of liquid during meals.
  • You will be given medicine to help reduce nausea and vomiting.
Rash (Common)
  • Usually mild and short-lived
  • Generally appears on the arms and trunk (occasionally on the face)
  • May be itchy
  • May appear as a flat, discolored area on the skin or as a small raised bump
  • Avoid prolonged exposure to heat.
  • Use creams or moisturizers regularly. Try wearing cotton gloves on your hands.
  • Avoid using perfume, cologne or aftershave since these products can be irritating to the skin.
  • Your healthcare provider may prescribe creams (mild steroids, antihistamines or antibiotics) to help treat the rash.
  • The rash may improve on its own without any treatment.
  What Are The Other Possible Side Effects? Listed below are additional side effects found with this treatment. It does not list all possible side effects. For more information, talk with your healthcare provider.

Common Side Effects

  • Fatigue

Less Common Side Effects

  • Indigestion
  • Back pain
  • Insomnia

Rare Side Effects

  • Abdominal pain