Patient Handout: Neratinib (Nerlynx)

What is Neratinib?

Neratinib, marketed under the brand name Nerlynx, is a medication used to treat HER2-positive breast cancer in adults. It is typically prescribed for women who have completed treatment with other HER2-targeted therapies (like trastuzumab) and chemotherapy. Neratinib works by blocking the HER2 protein that is involved in the growth and spread of certain types of cancer, particularly breast cancer.

How Does Neratinib Work?

Neratinib is an HER2 inhibitor and is part of a class of drugs known as targeted therapies. HER2 is a protein found on the surface of some cancer cells, and it helps these cells grow and divide. Neratinib targets and blocks HER2, preventing cancer cells from growing and spreading. This helps slow down or stop the growth of cancer in HER2-positive breast cancer.

How is Neratinib Taken?

Neratinib is taken as an oral tablet:

• Dosage: The typical dose is 240 mg, which is 6 tablets taken once daily. Your provider may start you on a lower dose initially to see tolerance.
• When to Take: It is best to take neratinib with food, as this may help reduce stomach upset.
• How to Take: Swallow the tablets whole with a glass of water. Do not crush, chew, or break the tablets.
• Missed Dose: If you miss a dose, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take two doses at the same time.

Possible Side Effects

Neratinib can cause side effects. Some of the side effects are more common than others, and some can be serious. Contact your healthcare provider if you experience any of the following:

Common Side Effects:

• Diarrhea: Diarrhea is the most common side effect of neratinib. You may be given medication to help prevent or treat it. Drink plenty of fluids and notify your doctor if diarrhea is severe.
• Nausea and Vomiting: Some patients experience nausea and vomiting, especially in the first few weeks of treatment. Your doctor may prescribe anti-nausea medication to help manage this.
• Fatigue: Feeling tired or weak is common. Be sure to get plenty of rest.
• Appetite Loss: Some people lose their appetite while taking neratinib. Eating smaller, more frequent meals may help.
• Mouth Sores: Painful sores or ulcers in the mouth may occur. Use mouth rinses and good oral hygiene to help manage this.
• Rash: A skin rash may develop while taking neratinib. This is usually mild but can sometimes become more severe.

Serious Side Effects:

• Severe Diarrhea: Severe diarrhea can lead to dehydration. If diarrhea becomes severe (more than 4 times a day or with blood), contact your healthcare provider immediately.
• Liver Problems: Neratinib may cause liver issues. Symptoms of liver problems include yellowing of the skin or eyes (jaundice), dark urine, or pain in the upper right side of your abdomen. Let your doctor know if you experience any of these.
• Heart Problems: Though rare, neratinib can cause issues with heart function. Seek medical attention if you experience chest pain, shortness of breath, or dizziness.
• Severe Skin Reactions: Some patients may develop severe rashes, blistering, or peeling of the skin. If you experience these symptoms, contact your healthcare provider immediately.

Precautions Before Taking Neratinib

Before taking neratinib, inform your healthcare provider if you:

• Have liver problems: Neratinib can affect liver function. Your doctor may need to adjust your treatment or monitor your liver function closely.
• Have heart problems: If you have a history of heart disease or irregular heart rhythms, your doctor will monitor your heart function during treatment.
• Are pregnant or planning to become pregnant: Neratinib may harm an unborn baby. Avoid pregnancy during treatment, and use effective contraception. If you become pregnant during treatment, contact your doctor immediately.
• Are breastfeeding: Neratinib is not recommended while breastfeeding because it may pass into breast milk.
• Are taking other medications: Neratinib may interact with other medications, including over-the-counter drugs, vitamins, and herbal supplements. Make sure to inform your doctor about all the medications you are taking.

What to Avoid While Taking Neratinib

• Grapefruit and Grapefruit Juice: Avoid grapefruit or grapefruit juice, as it can increase the amount of neratinib in your blood, potentially increasing side effects.
• Infections: Neratinib can affect your immune system, making it harder for your body to fight infections. Try to avoid close contact with sick people and practice good hygiene.
• Live Vaccines: Live vaccines may not be safe while undergoing treatment with neratinib. Consult your doctor before receiving any vaccinations during treatment.

Regular Monitoring

Your healthcare provider will regularly monitor your health during treatment with neratinib, including:

• Blood Tests: To check liver function, blood counts, and overall health.
• Diarrhea Management: Since diarrhea is a common side effect, your doctor may give you medications to prevent or treat it.
• Heart Monitoring: If you have heart problems, your doctor will monitor your heart function during treatment.

When to Contact Your Doctor

Contact your healthcare provider if you experience any of the following:

• Severe diarrhea: Particularly if it leads to dehydration (weakness, dizziness, or lightheadedness).
• Liver problems: Yellowing of the skin or eyes, dark urine, or upper stomach pain.
• Severe rash or skin issues: If the rash worsens or blisters, contact your healthcare provider immediately.
• Heart issues: Chest pain, irregular heartbeat, or difficulty breathing.
• Mouth sores: If they become painful or prevent you from eating or drinking.

Disclaimer:

This handout is for educational purposes only and should not be considered medical advice. Always follow the instructions provided by your healthcare provider regarding treatment and care. For personalized advice, consult your healthcare provider or pharmacist.