tucatinib

What is the most important information I should know about tucatinib?

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

What is tucatinib?

Tucatinib is used together with other medicines (trastuzumab and capecitabine) to treat HER2-positive breast cancer. This combination chemotherapy is used when the cancer has spread to other parts of the body or cannot be removed with surgery.

Tucatinib is usually given after other treatments have failed.

Tucatinib may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking tucatinib?

Tell your doctor if you have ever had liver disease.

Tell your doctor right away if a pregnancy occurs while either the mother or the father is using tucatinib.

This medicine may affect fertility (ability to have children) in both men and women. However, it is important to use birth control to prevent pregnancy because tucatinib can harm an unborn baby.

You may need to prevent pregnancy or avoid breastfeeding for longer periods of time after you stop using capecitabine or trastuzumab. Read all medication guides you receive. Follow directions about pregnancy or breastfeeding after you stop combination chemotherapy.

How should I take tucatinib?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may take tucatinib with or without food.

Take the medicine at the same time each day, about every 12 hours.

If you vomit shortly after taking tucatinib, do not take another dose. Wait until your next scheduled dose time to take the medicine again.

Use all medications as directed and read all medication guides you receive. Do not change your dose or dosing schedule without your doctor's advice.

You will need frequent blood tests to check your liver function.

Throw away any unused tucatinib tablets 3 months after you first opened the bottle.

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

What should I avoid while taking tucatinib?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What are the possible side effects of tucatinib?

• severe or ongoing diarrhea;
• pain, blisters, bleeding, or severe rash in the palms of your hands or the soles of your feet;
• blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;
• a seizure;
• liver problems --loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
• low red blood cells (anemia) --pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet.

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common side effects may include:

• diarrhea;
• nausea, vomiting, stomach pain, loss of appetite;
• anemia;
• mouth sores;
• rash;
• headache, tiredness; or
• abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect tucatinib?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Other drugs may affect tucatinib, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Where can I get more information?

Your pharmacist can provide more information about tucatinib.