Nerlynx (neratinib) is a prescription drug that’s used to treat certain types of breast cancer. The drug comes as a tablet that you swallow. It’s usually taken once per day.

Nerlynx is prescribed to treat the following types of breast cancer in adults:

Nerlynx is prescribed after you’ve already had other treatments for your cancer. This may include surgery, certain medications, or both.

The active ingredient in Nerlynx is neratinib. (An active ingredient is what makes a drug work.) Nerlynx belongs to a group of drugs called kinase inhibitors.

This article describes the dosages of Nerlynx, as well as its strength and how to take it. To learn more about Nerlynx, see this in-depth article.

* Chemotherapy refers to traditional drugs prescribed to treat cancer.

This section describes the usual dosages of Nerlynx. Keep reading to learn more.

What is Nerlynx’s form?

Nerlynx is available as a tablet that you swallow.

What strength does Nerlynx come in?

Nerlynx comes in one strength of 40 milligrams (mg).

What are the usual dosages of Nerlynx?

Your doctor will likely start by prescribing the recommended dosage of Nerlynx. They may adjust your dosage if you have side effects with the medication.

The information below describes dosages that are commonly prescribed or recommended. But be sure to follow the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.

The usual Nerlynx dosage for adults with types of HER2-positive breast cancer depends on the severity of the condition.

Dosage for early stage breast cancer

The usual dosage of Nerlynx for early stage HER2-positive breast cancer is 6 tablets (240 mg total) taken once per day.

Dosage to reduce the risk of diarrhea

Your doctor may suggest a different starting dosage schedule to reduce the risk of diarrhea, a common side effect of Nerlynx. See the section above called “Dosage for early stage breast cancer” for more information.

If you still have diarrhea, talk with your doctor. They may adjust your dosage of Nerlynx and recommend other medications to help manage your diarrhea.

Dosage for advanced or metastatic breast cancer

For advanced or metastatic HER2-positive breast cancer, the recommended dose of Nerlynx is 240 mg. You’ll take this dose once daily.

To treat this condition, doctors prescribe Nerlynx along with another medication called capecitabine (Xeloda). Talk with your doctor or pharmacist if you have questions about your dosage of Xeloda.

Dosage to reduce the risk of diarrhea

Your doctor may suggest a different starting dosage schedule to reduce the risk of diarrhea, a common side effect of Nerlynx. See the section above called “Dosage for advanced or metastatic breast cancer” for more information.

If you still have diarrhea, talk with your doctor. They may adjust your dosage of Nerlynx and recommend other medications to help manage your diarrhea.

Is Nerlynx taken long term?

How long your condition will be treated with Nerlynx depends on the severity of your condition.

For early stage HER2-positive breast cancer, you can take Nerlynx for up to 1 year. You’ll take it as long as you don’t have serious side effects from the medication and your cancer doesn’t return.

For advanced or metastatic HER2-positive breast cancer, you’ll likely take Nerlynx long term. You’ll take Nerlynx as long as your cancer doesn’t worsen and you don’t have serious side effects from the medication.

If you have questions about how long your doctor recommends Nerlynx treatment for your condition, talk with your doctor.

Dosage adjustments

In certain cases, you may need dosage adjustments for Nerlynx.

If you have liver problems, your doctor may prescribe a lower dosage of Nerlynx for you. This depends on the severity of your liver problems, your liver function, and how well your liver is working.

Your doctor will discuss your dosage with you and explain any adjustments you may need.

The dosage of Nerlynx you’re prescribed may depend on several factors. These include:

  • the severity of the condition you’re taking the drug to treat
  • any side effects you may have
  • other medications you may be taking
  • other conditions you may have (see the “Dosage adjustments” section above)

Nerlynx is available as a tablet that you swallow. You’ll take Nerlynx once per day with food. Your dose and how often you take Nerlynx depends on the severity of your condition and whether you have side effects.

Here are some tips for taking Nerlynx:

  • Take Nerlynx with food at the same time each day. This will help the drug work effectively.
  • Do not crush, chew, or cut Nerlynx tablets. Swallow them whole. If you have difficulty swallowing tablets, see this article for tips on how to take this form of medication.
  • For the first 56 days of treatment with Nerlynx, your doctor will prescribe loperamide (Imodium) on a set schedule. The purpose of this treatment is to lower your risk of diarrhea, a common side effect of Nerlynx.
  • If you take an H2 blocker such as cimetidine (Tagamet) or famotidine (Pepcid), you’ll need to adjust the time that you take Nerlynx. Take your Nerlynx dose at least 2 hours before your dose of the H2 receptor blocker or at least 10 hours after it.
  • If you take an antacid, take Nerlynx at least 3 hours before or after you take the antacid.

For information on the expiration, storage, and disposal of Nerlynx, talk with your doctor or pharmacist.

Accessible drug containers and labels

Some pharmacies provide medication labels that:

  • have large print
  • use braille
  • feature a code you can scan with a smartphone to change the text to audio

Your doctor or pharmacist may be able to recommend pharmacies that offer these accessibility features if your current pharmacy doesn’t.

Let your pharmacist know if you have difficulty opening medication bottles. They may have tips to help, or they may be able to supply Nerlynx in an easy-open container.

If you miss a dose of Nerlynx, skip the missed dose and take your next dose at its usual time. Do not take two doses of Nerlynx at one time to make up for a missed dose. This can increase your risk of serious side effects.

If you need help remembering to take your dose of Nerlynx on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Do not take more Nerlynx than your doctor prescribes, as this can lead to harmful effects.

Symptoms of overdose

An overdose of Nerlynx may cause the drug’s side effects to become severe or worse than usual. Symptoms that have been reported include:

What to do in case you take too much Nerlynx

Call your doctor right away if you think you’ve taken too much Nerlynx. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Below are answers to some commonly asked questions about Nerlynx’s dosage.

Are Nerlynx’s dosages similar to the dosages of Herceptin?

No, they aren’t. The forms, strengths, and how often you take each drug are different.

Herceptin (trastuzumab), which is also prescribed to treat certain types of breast cancer, is given as an intravenous (IV) infusion (an injection into your vein given over time) by a healthcare professional. The dosage depends on the type and severity of the condition Herceptin is treating.

Nerlynx comes as tablets that you swallow. Its dosage is different from Herceptin’s, but it also depends on the type and severity of the condition being treated.

To learn more about how these drugs compare, talk with your doctor.

How long does it take for Nerlynx to start working?

Nerlynx starts to work after your first dose. How long it takes to work can vary. It depends on how your body responds to the treatment and the severity of your condition. Because of how the drug works, you likely won’t feel it working in your body.

Your doctor will monitor you during treatment to check whether the drug is working to treat your condition. If you have other questions about what to expect from your Nerlynx treatment, talk with your doctor.

The sections above describe the usual dosages provided by Nerlynx’s manufacturer. If your doctor recommends this drug, they’ll prescribe the dosage that’s right for you.

Remember, you should not change your dosage of Nerlynx without your doctor’s recommendation. Only take Nerlynx exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask your doctor:

  • If I experience side effects from Nerlynx, can I keep taking a low dose of the medication?
  • Will I need a dosage adjustment for Nerlynx if I lose weight?
  • How does the dosage of Nerlynx compare with the dosage of Verzenio (abemaciclib)?

To learn more about Nerlynx, see this article: All About Nerlynx.

For information about other breast cancer drugs, explore this page.

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.