Lapatinib Tablets

What is this medication?

LAPATINIB (la PA ti nib) treats breast cancer. It works by blocking a protein that causes cancer cells to grow and multiply. This helps to slow or stop the spread of cancer cells.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.

COMMON BRAND NAME(S): Tykerb

What should I tell my care team before I take this medication?

They need to know if you have any of these conditions:

• Heart disease
• High blood pressure
• Irregular heartbeat or rhythm
• Liver disease
• Low levels of magnesium in the blood
• Low levels of potassium in the blood
• An unusual reaction to lapatinib, other medications, foods, dyes, or preservatives
• Pregnant or trying to get pregnant
• Breast-feeding

How should I use this medication?

Take this medication by mouth. Take it as directed on the prescription label at the same time every day. Do not cut, crush, or chew this medication. Swallow the tablets whole. Take it on an empty stomach, at least 1 hour before or 1 hour after food. Keep taking it unless your care team tells you to stop.

Do not take this medication with grapefruit juice.

Talk to your care team about the use of this medication in children. Special care may be needed.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

If you miss a dose, skip it. Take your next dose at the normal time. Do not take extra or 2 doses at the same time to make up for the missed dose.

What may interact with this medication?

Do not take this medication with any of the following:

• Cisapride
• Dronedarone
• Fluconazole
• Pimozide
• Posaconazole
• Saquinavir
• Thioridazine

This medication may also interact with the following:

• Certain antibiotics, such as clarithromycin, erythromycin, telithromycin
• Certain antivirals for HIV or AIDS
• Certain medications for depression, anxiety, or other mental health conditions
• Certain medications for fungal infections, such as itraconazole, ketoconazole, voriconazole
• Certain medications for seizures, such as carbamazepine, phenobarbital, phenytoin
• Certain medications for tuberculosis, such as rifabutin, rifampin, and rifapentine
• Dexamethasone
• Digoxin
• Nefazodone
• Other medications that cause heart rhythm changes, such as dofetilide or ziprasidone
• St. John's wort

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medication?

Visit your care team for regular checks on your progress. It may be some time before you see the benefit from this medication.

This medication may make you feel generally unwell. This is not uncommon as chemotherapy can affect healthy cells as well as cancer cells. Report any side effects. Continue your course of treatment even though you feel ill unless your care team tells you to stop.

Talk to your care team if you or your partner wish to become pregnant or think you might be pregnant. This medication can cause serious birth defects if taken during pregnancy or for 1 week after the last dose. A negative pregnancy test is required before starting this medication. A reliable form of contraception is recommended while taking this medication and for 1 week after the last dose. Talk to your care team about reliable forms of contraception. Do not father a child while taking this medication or for 1 week after the last dose. Use a condom while having sex during this time period.

Do not breast-feed while taking this medication and for 1 week after the last dose.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible:

• Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
• Dry cough, shortness of breath or trouble breathing
• Heart failure—shortness of breath, swelling of the ankles, feet, or hands, sudden weight gain, unusual weakness or fatigue
• Heart rhythm changes—fast or irregular heartbeat, dizziness, feeling faint or lightheaded, chest pain, trouble breathing
• Liver injury—right upper belly pain, loss of appetite, nausea, light-colored stool, dark yellow or brown urine, yellowing skin or eyes, unusual weakness or fatigue
• Redness, blistering, peeling, or loosening of the skin, including inside the mouth
• Severe or prolonged diarrhea

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

• Fatigue
• Nausea
• Pain, redness, or swelling with sores inside the mouth or throat
• Trouble sleeping
• Vomiting

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medication?

Keep out of the reach of children and pets.

Store at room temperature between 20 and 25 degrees C (68 and 77 degrees F). Get rid of any unused medication after the expiration date.

To get rid of medications that are no longer needed or have expired:

• Take the medication to a medication take-back program. Check with your pharmacy or law enforcement to find a location.
• If you cannot return the medication, check the label or package insert to see if the medication should be thrown out in the garbage or flushed down the toilet. If you are not sure, ask your care team. If it is safe to put it in the trash, take the medication out of the container. Mix the medication with cat litter, dirt, coffee grounds, or other unwanted substance. Seal the mixture in a bag or container. Put it in the trash.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.