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.