If you have advanced or metastatic breast cancer, your doctor might suggest Tykerb as a treatment option. It’s a prescription drug used to treat certain kinds of HER2-positive (HER2+) breast cancer in adults. You’ll likely continue to take Tykerb unless you get bothersome side effects or your cancer grows during treatment.

Depending on the type of HER2+ metastatic breast cancer you have, a doctor will usually prescribe Tykerb together with either Xeloda (capecitabine) or Femara (letrozole).

Lapatinib is an active ingredient in Tykerb. An active ingredient is what makes a drug work.

Tykerb is a tablet that you swallow. It is available in one strength.

For more information about Tykerb, including details about its uses, see this in-depth article.

Tykerb can cause mild to serious side effects. Continue reading to learn more.

Some people may experience side effects during Tykerb treatment. Some side effects are more common than others.

Tykerb has been reported to have some side effects.

The side effects explained section is where you can learn more about this side effect.

The side effects of Tykerb are not as bad as they were in studies. This drug may cause other side effects. Mild side effects and some serious ones are described.

Mild side effects can be caused by Tykerb. There have been some mild side effects with this drug.

The side effects explained section is where you can learn more about this side effect.

“These side effects should be temporary. Some may be easy to manage. If you have any symptoms that bother you, talk to your doctor or pharmacist. Unless your doctor recommends it, don’t stop taking Tykerb.”

Tykerb may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Tykerb, visit MedWatch.

Side effects can be caused by treatment with Tykerb. People with certain medical conditions are at an increased risk.

There have been serious side effects reported with Tykerb.

If you develop serious side effects while taking Tykerb, call your doctor. If the side effects seem life threatening or you think you have a medical emergency, immediately call the emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.
† Tykerb has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.

Get answers to questions about Tykerb.

Are my risks of side effects higher if I take Xeloda with Tykerb?

You will take Tykerb with Xeloda (capecitabine) or Femara (letrozole), depending on the type of HER2-positive (HER2+) metastatic breast cancer you have.

There wasn’t a significant difference in side effects when people took Tykerb with Xeloda versus Femara. (You can check out the drug’s full prescribing information for details of the studies.)

Mild side effects may be different, but your risk of serious side effects is not expected to change.

Talk to your doctor or pharmacist about it.

How do the side effects of Tykerb compare with those of Herceptin?

Both Tykerb and Herceptin treat certain types of HER2-positive (HER2+) metastatic breast cancer. A doctor may also prescribe Herceptin to treat certain digestive tract cancers.

These medications can cause side effects.

They have different side effects.

For example, Herceptin can cause tumor lysis syndrome, a rare but serious side effect that occurs when a large number of cancer cells die in a short time and release their contents into your bloodstream. There have been no reports of this side effect with Tykerb.

But Tykerb can cause long QT syndrome (a condition that affects your heart’s electrical activity), but there were no reports of this in Herceptin’s studies. Tykerb can also cause liver problems, but there were no reports of this side effect with Herceptin.

If you want to learn more about how these drugs compare, you should talk to your doctor or pharmacist.

Will Tykerb cause any long-term side effects?

It is possible. Mild, temporary, and may go away without treatment, are some of the side effects of Tykerb.

Long-term side effects can be caused by Tykerb. These are side effects that can happen.

  • Continue for a long time after you stop taking the drug.
  • After you have taken Tykerb for a long time, start.

Some of the long-term side effects reported in Tykerb’s studies include:

* To learn more about this side effect, see the “Side effects explained” section below.
† Tykerb has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.

If you have questions about the long-term effects of Tykerb, you should talk to your doctor or pharmacist.

Tykerb may cause some side effects.

Risk of liver damage

Tykerb has a boxed warning about the risk of liver damage. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Liver damage was reported in Tykerb’s studies. Liver problems can be severe, and deaths have been reported. This side effect can occur within days of starting Tykerb but has also occurred months after treatment began.

Liver damage may not cause symptoms right away. It may go unnoticed except for changes to certain blood tests. (See “What might help” just below.) But it’s possible to have symptoms such as:

What might help

Before you begin treatment, your doctor will order blood tests to check your liver function. They’ll also order these tests every 4 to 6 weeks while you’re taking Tykerb.

If you notice symptoms of damage to the bile duct, you should immediately contact your doctor. If you have symptoms or your doctor notices changes in your blood test results, they may be you.

  • Take a lower dose of the drug.
  • Take another blood test to see if your results have returned to normal.
  • Take Tykerb only temporarily.

Cardiac side effects

It’s possible to have cardiac (heart-related) side effects from Tykerb. Your risk of heart-related side effects increases if you have an existing heart condition, such as heart failure or a heart rhythm problem.

There are specific heart-related side effects reported in Tykerb.

  • Long QT syndrome. The QT interval is part of your heart rhythm. Long QT syndrome is a condition in which this interval becomes too long. This is a type of heart arrhythmia (irregular heartbeat).
  • Worsened left ventricular function. The left ventricle is the part of your heart responsible for pumping blood to the rest of your body. Issues with left ventricle function can lead to problems with blood supply to your body. It can even lead to heart failure. This side effect is most common in the first 12 weeks of treatment but may occur at any time.

There are symptoms of heart-related side effects caused by Tykerb.

What might help

Before you start Tykerb treatment, your doctor will check your heart health. They’ll also check your electrolyte levels, such as your blood potassium and magnesium levels. They may prescribe treatment to correct any issues they find before prescribing Tykerb for you.

Your doctor will keep an eye on your heart health while you take Tykerb. If you notice symptoms of a heart problem, call your doctor. They may have you if your symptoms are more severe.

  • The drug should be lowered in your dose.
  • If you stop taking Tykerb, you will be able to see if it helps your symptoms.
  • Take Tykerb permanently.

Severe skin reactions

Since Tykerb was approved for use, there have been rare reports of severe skin infections. These reactions can be life threatening and include:

These reactions can have symptoms.

What might help

If you notice a severe skin reaction while taking Tykerb, you should call your doctor or seek emergency medical care. These reactions can be life threatening and need treatment in a hospital.

If you develop a severe skin reaction, your doctor will likely stop you from taking Tykerb. If this happens, they can discuss alternative treatments for your cancer.

Hand-foot syndrome

Hand-foot syndrome is a possible side effect of Tykerb. In studies, this was more common among people who took Tykerb together with Xeloda (capecitabine). But it can also happen when you take Tykerb with Femara (letrozole).

Hand-foot syndrome is a condition that causes burning, numbness, tingling, and swelling in your feet or hands. This burning can be intense, and, in severe cases, your skin can blister or develop ulcers.

What might help

If you develop symptoms of hand-foot syndrome while taking Tykerb, call your doctor. They may recommend treatment for your symptoms. Examples include:

If you have severe symptoms, your doctor may have to stop taking Tykerb.

Allergic reaction

Like most drugs, Tykerb can cause an allergic reaction in some people. While allergic reactions weren’t reported in the drug’s studies, they have been reported since the drug was approved for use.

Mild to serious symptoms can be present.

What might help

If you have mild symptoms of an allergic reaction, such as a mild There is a There is a rash.., call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine)
  • A product that is applied to the skin.

If your doctor confirms that you have an allergic reaction to Tykerb, they will decide if you should continue taking it.

If you have a severe allergic reaction, you should call the emergency number. These symptoms could be life threatening and need immediate medical care.

If your doctor confirms you have had a serious allergic reaction to Tykerb, they may have you switch to a different treatment.

Keeping track of side effects

Take notes on any side effects you are having during your Tykerb treatment. You can share this information with your doctor. This is helpful when you are starting to use a combination of treatments.

Side effect notes can include things.

  • When you had the side effect, what dose of the drug was taking?
  • How soon did you experience the side effect?
  • What are your symptoms?
  • How did it affect your daily activities?
  • What other drugs were you taking?
  • Other information is important to you.

Sharing notes with your doctor will help them learn more about how Tykerb affects you. If needed, they can use this information to adjust your treatment plan.

There are some things to consider before starting Tykerb treatment.

Boxed warning: Risk of liver damage

Tykerb has a boxed warning for the risk of liver damage. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). Liver damage may be severe, and deaths have been reported in studies.

To learn more, see the “Side effects explained” section above.

Other warnings

If you have a medical condition that affects your health, Tykerb may not be right for you. Talk to your doctor about your health history before you start taking this drug. The list has factors to consider.

Heart problems. Tykerb can cause heart-related side effects, including abnormal heart rhythm or problems with heart function. Your risk may be higher if you have an existing heart problem, such as heart failure. Your doctor can determine whether it’s safe for you to take Tykerb. If they decide to prescribe it for you, they may monitor your heart health closely during treatment.

Low magnesium or potassium level. Tykerb can cause problems with your heart rhythm as a side effect. Your risk of this is higher if you have low magnesium or potassium levels. Your doctor will likely want to treat your low levels of these electrolytes (essential minerals) before prescribing Tykerb for you.

Allergic reaction. If you’ve had an allergic reaction to Tykerb or any of its ingredients, your doctor will likely not prescribe it for you. Ask them about other medications that might be better treatment options.

Alcohol and Tykerb

There are no known interactions between drinking alcohol and taking Tykerb. But alcohol could worsen certain side effects this drug may cause, such as There is a lot of diarrhea., nausea, and liver problems.

If you consume alcohol, talk to your doctor about how much you should take.

Pregnancy and breastfeeding while taking Tykerb

Tykerb is not recommended for pregnant women or breastfeeding.

  • If you can become pregnant, your doctor will order a test to confirm it, and then prescribe Tykerb. Birth control should be used for at least 1 week after you take your last dose of Tykerb.
  • You should not breastfeeding after your last dose of Tykerb.

Talk to your doctor about the treatments for breast cancer.

Treatment with Tykerb can cause mild to serious side effects. Mild side effects are common, especially There is a lot of diarrhea. and nausea. Serious side effects can also happen.

“Talk to your doctor before starting treatment. Ask questions that will help you understand the drug’s side effects. Some examples will help you start.”

  • Can my medications interact with Tykerb and increase my risk of side effects?
  • Does my medical history increase my risk of side effects?
  • Is there a lower dose I can try if I have side effects from Tykerb?

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Q:

Is Tykerb safe for older people? There are unique side effects of the drug that older adults may experience.

Anonymous

A:

Yes, in general. Older adults can use Tykerb.

Tykerb’s studies included adults ages 65 years and above. Researchers did not notice significant differences in side effects between older and younger adults.

Older adults are more likely to take multiple drugs. It is possible for these drugs to interact with Tykerb, which can increase the risk of side effects. It is important to talk with your doctor or pharmacist about all your medications so they can check for potential interactions.

Older adults are also more likely to have problems affecting their heart or liver. Heart or liver conditions can increase the risk of side effects, particularly heart-related side effects and liver damage. (To learn more about these, see “Side effects explained” above.) Your doctor can tell you more about whether any of your medical conditions increase your risk of side effects from Tykerb.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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.