Neratinib is used to treat breast cancer. Neratinib belongs to a class of drugs known as kinase inhibitors. It works by slowing or stopping the growth of cancer cells.

Read the Patient Information Leaflet if available from your pharmacist before you start taking neratinib and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with food as directed by your doctor, usually once daily. Swallow the medication whole. Do not crush, chew, or split the tablets. Avoid handling or touching crushed or broken tablets.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.

The dosage is based on your medical condition and response to treatment. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.

To help prevent diarrhea, your doctor should prescribe anti-diarrhea medication (such as loperamide) for you to take on a regular schedule during the first 2 months of treatment with neratinib. Follow your doctor's directions to keep taking anti-diarrhea medication on a regular schedule or to take it only as needed.

Medications which reduce or block stomach acid (such as proton pump inhibitors-PPIs, H2 blockers, antacids) may reduce the absorption of neratinib, making it work less well. Do not take PPIs (such as omeprazole, lansoprazole) while using this medication. If you take an antacid, take it at least 3 hours before taking neratinib. If you take a H2 blocker (such as famotidine, ranitidine), take it at least 10 hours before or at least 2 hours after taking neratinib.

Avoid eating grapefruit or drinking grapefruit juice while using this medication unless your doctor or pharmacist says you may do so safely. Grapefruit can increase the chance of side effects with this medicine. Ask your doctor or pharmacist for more details.

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

Nausea, vomiting, mouth sores/pain, stomach/abdominal pain, loss of appetite, weight loss, tiredness, dry skin, nail changes, or muscle spasms may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.

Diarrhea is a common side effect. Drink plenty of fluids as directed by your doctor to lower your risk of dehydration. Your doctor should prescribe anti-diarrhea medication (such as loperamide) to help control your symptoms. Tell your doctor right away if you develop diarrhea that is severe or doesn't stop, or signs of dehydration (such as unusual decreased urination, unusual dry mouth/thirst, fast heartbeat, dizziness/lightheadedness). Your doctor may prescribe additional anti-diarrhea medications or temporarily stop/adjust your dose of neratinib.

Tell your doctor right away if you have any serious side effects, including:

• severe stomach/abdominal pain
• yellowing eyes/skin
• dark urine
• signs of kidney problems (such as change in the amount of urine)

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

Neratinib can commonly cause a mild rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe allergic reaction. Get medical help right away if you develop any rash.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking neratinib, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• liver disease

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using neratinib. Neratinib may harm an unborn baby. Your doctor should order a pregnancy test before you start this medication. Women using this medication should ask about reliable forms of birth control during treatment and for 1 month after the last dose. Men using this medication should ask about reliable forms of birth control during treatment and for 3 months after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this medication passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this medication and for at least 1 month after the last dose. Consult your doctor before breastfeeding.

See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are:

• drugs that reduce stomach acid (such as antacids, H2 blockers such as famotidine/ranitidine, proton pump inhibitors such as omeprazole/lansoprazole)

Other medications can affect the removal of neratinib from your body, which may affect how neratinib works. Examples include azole antifungals (such as ketoconazole, itraconazole), macrolide antibiotics (such as clarithromycin), nefazodone, HIV protease inhibitors (such as indinavir, nelfinavir), rifamycins (such as rifabutin, rifampin), ritonavir, St. John's wort, drugs used to treat seizures (such as carbamazepine, phenytoin), telithromycin, among others.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab and/or medical tests (such as liver function) should be done while you are taking this medication. Keep all medical and lab appointments.

If you miss a dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).