Tukysa (tucatinib) is a brand-name prescription medication. The Food and Drug Administration (FDA) has approved it to treat specific types of breast cancer in certain adults.

Specifically, Tukysa is prescribed to treat HER2-positive breast cancer that’s unresectable (locally advanced and cannot be removed by surgery) or is metastatic. Tukysa is approved for use in adults who have already tried certain medications to treat their breast cancer.

Tukysa comes as an oral tablet. It belongs to a group of drugs called kinase inhibitors.

Currently, Tukysa is only available as a brand-name medication. It’s not available as a generic version at this time.

Tukysa dosage summary chart

The following chart summarizes Tukysa’s dosage. Your doctor will determine the dosage that’s best for you.

Tukysa formTukysa strengthsUsual Tukysa dosage
oral tablet• 50 milligrams (mg)
• 150 mg
300 mg twice daily

For information about the dosage of Tukysa, including its strengths and how to take the drug, keep reading. For a comprehensive look at Tukysa, including more information about its uses, see this article.

This article describes typical dosages for Tukysa provided by the drug’s manufacturer. When taking Tukysa, always follow the dosage prescribed by your doctor.

Your doctor will recommend the best dosage of Tukysa for you. Below is some information about the typical dosing of Tukysa.

Tukysa form

Tukysa comes as an oral tablet.

Tukysa strengths

Tukysa comes in two strengths:

  • 50 milligrams (mg)
  • 150 mg

Typical dosages

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage, timing, and frequency for your needs.

The dosage of Tukysa is usually the same for most people. However, certain factors may affect the dosage your doctor prescribes. (To learn more, see the “Factors that can affect your dosage” section below.) Your doctor will not need to use a Tukysa dosage calculator to determine your dose of Tukysa. The drug’s dosage is not based on body weight or by volume.

Dosage for locally advanced breast cancer

Tukysa is approved to treat adults with HER2-positive breast cancer that’s unresectable (locally advanced and cannot be removed through surgery). The recommended dosage for this use is 300 mg twice daily.

You will likely take Tukysa along with Herceptin (trastuzumab) and Xeloda (capecitabine) to treat this form of breast cancer.

Dosage for metastatic breast cancer

The recommended dosage of Tukysa to treat metastatic breast cancer is 300 mg twice daily.

You will likely take Tukysa along with Herceptin (trastuzumab) and Xeloda (capecitabine) for this use.

Long-term treatment

Tukysa is meant to be used as a long-term treatment. If you and your doctor determine that Tukysa is safe and effective for you, you’ll likely take it long term.

Your doctor will prescribe this drug for as long as it is effective for your condition. Or they’ll prescribe it for as long as you don’t develop serious side effects. (To learn more about the side effects of Tukysa, see this article.)

The Tukysa dosage your doctor prescribes will depend on several factors. These include:

  • side effects that you may have from Tukysa treatment
  • other medications that you’re taking
  • other medical conditions you may have

Dosage adjustments

Your doctor may recommend changes to your Tukysa dosage based on certain conditions. For example, they may prescribe you a lower dosage of Tukysa if you:

  • have liver problems before starting Tukysa treatment
  • develop serious side effects from Tukysa treatment,* such as severe diarrhea or liver damage

Also, certain medications can interact with Tukysa and may increase your risk of side effects from the drug.† So, if you’re taking certain drugs, your doctor may recommend a lower dose of Tukysa. Before starting Tukysa treatment, be sure to tell your doctor about any other medications that you take. They can help determine the best dosage of Tukysa for you.

* To learn more about side effects of Tukysa, see this article.
† For information about the drugs that can interact with Tukysa, see this article.

Tukysa comes as a tablet that you’ll swallow whole. Do not chew, crush, or split your tablets. If you notice that a tablet is broken or cracked, do not take it. You can take Tukysa with or without food.

You’ll take your Tukysa dose twice daily, 12 hours apart at the same time each day. This helps maintain a steady level of the drug in your body so Tukysa can work effectively.

If you have trouble swallowing tablets, see this article for tips on how to take this form of medication. You can also talk with your doctor or pharmacist if you have questions about how to take Tukysa.


If you’re having trouble reading your prescription label, talk with your doctor or pharmacist. Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you’re having trouble opening medication bottles, ask your pharmacist about putting Tukysa in an easy-open container. They also may recommend tools that can make it easier to open bottles.

If you miss a dose of Tukysa, skip your missed dose and take your next dose at your normally scheduled time. However, if you missed a dose and you’re unsure when to take the next one, talk with your doctor or pharmacist. They can help determine when you should take your next Tukysa dose.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

It’s important that you do not take more Tukysa than your doctor prescribes. For some medications, taking more than the recommended amount may lead to side effects or overdose.

If you take more than the recommended amount of Tukysa

Call your doctor right away if you believe you’ve taken too much Tukysa. Another option is to call the American Association of Poison Control Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

Below are some questions about Tukysa and its dosage.

Can I take Tukysa for bodybuilding? If so, what is the dosage?

No, you should not take Tukysa for bodybuilding. There is not an approved Tukysa dosage for this purpose. The only approved uses of Tukysa are to treat certain types of locally advanced or metastatic breast cancer.

Other breast cancer medications, such as Arimidex (anastrozole), are sometimes used in bodybuilding. Some people take Arimidex to decrease hormone-related side effects from taking anabolic steroids. However, this is not a recommended use of Arimidex or Tukysa.

It’s important that you do not take Tukysa without a prescription from your doctor or another healthcare professional. You also should not take the drug for conditions it has not been prescribed to treat. Doing so is an example of misuse. (Misuse means taking a drug differently from how your doctor prescribed it.)

If you have questions about taking certain drugs for bodybuilding, talk with your doctor.

Can I take vitamins, such as vitamin B12, along with Tukysa? Will that change my dosage?

In most cases, you can take Tukysa with vitamins and supplements, including vitamin B12. It is unlikely that your doctor will change your Tukysa dosage if you take vitamins.

However, you should not take Tukysa with St. John’s wort. This herb is sometimes used to treat depression, and it can make Tukysa less effective.

Tukysa can also interact with certain other drugs. So, it is important to tell your doctor or pharmacist about any other medications, vitamins, or supplements you take. They may need to change your Tukysa dose depending on what other drugs you take. (For information about the drugs that can interact with Tukysa, see this article.)

If you have questions about taking vitamins with Tukysa, talk with your doctor or pharmacist.

The dosages in this article are typical dosages provided by the drug manufacturer. If your doctor recommends Tukysa for you, they will prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes for you.

As with any drug, never change your dosage of Tukysa without your doctor’s recommendation. If you have questions about the dosage of Tukysa that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Tukysa. These additional articles might be helpful to you:

Disclaimer: Medical News Today 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.