Neratinib is used alone or with other medicines to treat early-stage HER2-positive breast cancer. Neratinib is also used to treat HER2-positive breast cancer that is advanced or has spread to other parts of the body (metastatic).

Neratinib is used for breast cancer only if your tumor tests positive for a protein called human epidermal growth factor receptor 2 (HER2). HER2 protein can speed the growth of cancer cells.

Neratinib is given after you have received certain other cancer medicines.

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

Neratinib can cause severe diarrhea, which can be life-threatening if it leads to dehydration. You may be given anti-diarrhea medications for the first 2 months of treatment with neratinib.

Call your doctor if you are sick with severe diarrhea, or you also have weakness, dizziness, or a fever.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

The usual dose is 6 tablets taken once daily. Take the medicine with food, at the same time each day.

You may need to take this medicine daily for up to one year. Neratinib is sometimes taken daily in 21-day treatment cycles until the medicine stops working or until you have serious side effects.

Your doctor will determine how long to treat you with this medicine. Follow your doctor's dosing instructions very carefully.

Swallow the tablet whole and do not crush, chew, or break it.

Neratinib can cause severe diarrhea, which can be life-threatening if it leads to dehydration. For the first 2 months of treatment with neratinib, you may need to take medication to prevent or quickly treat diarrhea.

Your doctor may recommend you have an anti-diarrhea medicine such as loperamide (Imodium) available at all times while you are taking neratinib. Take the anti-diarrhea medicine exactly as prescribed by your doctor.

To best control diarrhea, you may need to follow a special diet. Get familiar with the list of foods you should eat or avoid to help control diarrhea. You may also need to drink extra fluids to keep from getting dehydrated.

Tell your doctor if you have more than 2 bowel movements in 1 day.

Call your doctor if you are sick with severe diarrhea, or you also have weakness, dizziness, or a fever. You may need to stop taking neratinib for a short time.

You may need frequent blood tests.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Breast Cancer -- Adjuvant:

240 mg orally once a day continuously for 1 year

NOTE: Antidiarrheal prophylaxis is recommended during the first 2 cycles (56 days) of therapy and should be initiated with the first dose. Titrate loperamide to 1 to 2 bowel movements per day.
MANUFACTURER SUGGESTED PROPHYLACTIC LOPERAMIDE DOSING:
-Weeks 1 and 2 (days 1 through 14): 4 mg orally 3 times a day
-Weeks 3 through 8 (days 15 through 56): 4 mg orally 2 times a day
-Weeks 9 through 52 (days 57 through 365): 4 mg as needed (not to exceed 16 mg per day)

Use: For the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer (to follow adjuvant trastuzumab-based therapy)

Tell your doctor if you have ever had:

• liver disease.

You may need to have a negative pregnancy test before starting this treatment.

Neratinib can harm an unborn baby or cause birth defects if the mother or the father is using neratinib.

• If you are a woman, do not use neratinib if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 1 month after your last dose.

• If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 3 months after your last dose.

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

Do not breastfeed while using this medicine, and for at least 1 month after your last dose.

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

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include severe diarrhea or vomiting, stomach pain, increased thirst, decreased urination, dark urine, dizziness, or hot and dry skin.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Do not eat grapefruit or drink grapefruit juice while taking this medication.

Grapefruit may interact with neratinib and lead to unwanted side effects. Avoid the use of grapefruit products.

Ask your doctor before using an antacid or stomach acid reducing medicine. Use only the type your doctor recommends.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Neratinib may cause serious side effects. Call your doctor at once if you have:

• severe or ongoing diarrhea;

• pain or burning when you urinate;

• kidney problems--little or no urination, swelling in your feet or ankles, feeling tired or short of breath; or

• liver problems--right-sided upper stomach pain, vomiting, tiredness, fever, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

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

Common side effects of neratinib may include:

• kidney problems;

• abnormal liver function tests;

• diarrhea, constipation;

• painful urination;

• nausea, vomiting, stomach pain, bloating;

• upset stomach, loss of appetite;

• dizziness, feeling weak or tired;

• nosebleed;

• rash, dry skin, problems with your fingernails or toenails;

• dry mouth, mouth sores;

• back pain, joint pain, muscle spasms;

• weight loss; or

• cold symptoms such as stuffy nose, sneezing, sore throat.

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.

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.

If you also take an antacid: Wait at least 3 hours after taking the antacid before you take neratinib.

If you also take a stomach acid reducer: Take your neratinib dose 2 hours before or 10 hours after you take the other medicine (this includes cimetidine, famotidine, nizatidine, ranitidine, Axid, Pepcid, Tagamet, Zantac, and others).

You should not use certain stomach acid reducers, such as esomeprazole, lansoprazole, omeprazole, pantoprazole Nexium, Prevacid, Prilosec, Protonix, and others.

Other drugs may affect neratinib, 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.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to neratinib.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.