Tykerb (lapatinib) is a prescription brand-name medication. It’s approved by the Food and Drug Administration (FDA) to treat some types of HER2-positive (HER2+) breast cancer in adults. HER2 is a protein found in some breast cancers that signals cancer cell growth. Tykerb works by blocking these signals.
Tykerb is a targeted chemotherapy drug that you take with another drug to treat breast cancer. You’ll take Tykerb with either Xeloda (capecitabine) or Femara (letrozole). Your doctor will give you more information about the other drugs you may take with Tykerb.
If Tykerb effectively keeps your cancer from growing, you may take it long-term.
Here are some fast facts on Tykerb:
- Active ingredient: lapatinib
- Drug class: tyrosine-kinase inhibitor
- Drug form: oral tablet, which comes in one strength of 250 milligrams (mg)
Like other drugs, Tykerb can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Tykerb, including details about how to use it, see this article.
These are just a few of the more common side effects reported by people who took Tykerb in clinical studies. These side effects can vary depending on which drug you’re taking with Tykerb.
More common side effects in people taking Tykerb with the chemotherapy drug Xeloda (capecitabine) include:
- mild diarrhea
- hand-foot syndrome (redness, blistering, and/or swelling that affects your hands and feet)*
- nausea and vomiting
- rash*
- fatigue (lack of energy)
More common side effects in people taking Tykerb with the cancer drug Femara (letrozole) include:
- mild diarrhea
- rash*
- nausea
- fatigue
* For more information on this side effect, see “Side effect specifics” below.
Mild side effects can occur with Tykerb use. This list doesn’t include all possible mild side effects of the drug. These side effects can vary depending on which drug you’re taking with Tykerb. For more information, you can refer to Tykerb’s patient information.
Mild side effects that people have reported with Tykerb include:
- rash*
- diarrhea
- nausea
- vomiting
- fatigue (lack of energy)
- hand-foot syndrome (redness, blistering, and/or swelling that affects your hands and feet)*
- stomatitis (sores or swelling in your mouth)
- headache
- hair loss or thinning
- shortness of breath
- pain in your arm, back, or leg
- dry or itchy skin
- loss of appetite
- indigestion
These side effects may be temporary, lasting a few days or weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.
Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Tykerb and want to tell the FDA about it, visit MedWatch.
* For more information on this side effect, see “Side effect specifics” below.
Tykerb may cause serious side effects. These side effects can vary depending on which drug you’re taking with Tykerb. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Tykerb’s patient information.
If you develop serious side effects while taking Tykerb, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.
Serious side effects that have been reported and their symptoms include:
- Long QT syndrome (lengthening of part of your heart rhythm). Symptoms can include:
- fainting for no known reason
- a fluttering feeling in your chest
- Decreased heart function. Symptoms can include:
- fatigue (lack of energy)
- swelling in your feet and lower legs
- weakness
- Lung problems, including interstitial lung disease and pneumonitis. Symptoms can include:
- dry cough that doesn’t go away
- shortness of breath
- Severe diarrhea.*
- Serious skin reactions.*
- Severe liver damage.*†
- Allergic reaction.*‡
* For more information on this side effect, see “Side effect specifics” below.
† Tykerb has a
‡ An allergic reaction is possible after using Tykerb. But this side effect wasn’t reported in clinical studies.
Tykerb may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.
What are the side effects of Tykerb when used with Xeloda?
Doctors prescribe Tykerb for use with another cancer drug, such as the chemotherapy drug Xeloda (capecitabine). More common side effects reported by people taking Tykerb with Xeloda in clinical trials include:
- diarrhea
- hand-foot syndrome (redness, blistering, and/or swelling that affects your hands and feet)*
- nausea and vomiting
- rash*
- fatigue (lack of energy)
For a complete list of Tykerb’s side effects, including side effects when used with Xeloda, see Tykerb’s prescribing information.
* For more information on this side effect, see “Side effect specifics” below.
How do side effects of Tykerb compare with those of Herceptin?
Tykerb and Herceptin (trastuzumab) are both approved to treat certain types of HER2-positive (HER2+)* breast cancer in adults. These two drugs can cause some similar side effects and some different ones as well. The table below lists the mild side effects of the drugs.
| Side effects of both Tykerb and Herceptin (taken individually) | Side effects of Tykerb | Side effects of Herceptin |
| • pain in your back or leg • diarrhea • fatigue (lack of energy) • headache • nausea and vomiting • rash† • shortness of breath | • hair loss • hand-foot syndrome (redness, blistering, and/or swelling that affects your hands and feet)† | • hot flashes • fluid retention (excess water in your body that can cause swelling) |
For a full comparison of Tykerb and Herceptin, including the side effects of each drug, check out this article.
* HER2 is a protein found in some breast cancers that signals cancer cell growth.
† For more information on this side effect, see “Side effect specifics” below.
Are there any long-term side effects of Tykerb?
Most side effects caused by Tykerb are mild and usually go away with time or with medical treatment.
However, some side effects caused by Tykerb may not go away and may require long-term treatment. Examples of long-term side effects that Tykerb may cause include:
- long QT syndrome (lengthening of part of your heart rhythm)
- decreased heart function
- lung problems, including interstitial lung disease and pneumonitis
- severe liver damage*
If you’re experiencing side effects while taking Tykerb and you’re concerned that they may be long-term, talk with your doctor. They may suggest a treatment for your side effect. Or they may recommend that you stop taking Tykerb and try a different treatment for your cancer.
Talk with your doctor or pharmacist if you have additional questions about long-term side effects from Tykerb. They can provide information that’s specific for you and your health.
* Tykerb has a
Learn more about some of the side effects that Tykerb may cause.
Severe liver damage
Tykerb has a
Liver damage with Tykerb use can be severe. Very rarely, deaths from liver damage have been reported in people taking Tykerb.
Liver damage can develop within a few days or months after starting Tykerb treatment. Symptoms of severe liver damage can include:
- dark urine
- discomfort or pain in the upper-right part of your abdomen
- itchiness
- jaundice (yellowing of your skin and/or the whites of your eyes)
Before you start taking Tykerb, you’ll need to have liver function tests. You’ll have these blood tests every 4-6 weeks while you’re taking Tykerb. These tests help determine if your liver is working well enough for you to continue Tykerb treatment.
What you can do
If you experience any symptoms of liver damage while taking Tykerb, contact your doctor. They’ll likely recommend that you have additional tests to check your liver function. Depending on your test results and your symptoms, your doctor may have you stop taking Tykerb and switch to a different cancer drug.
Rash
Rash was a common side effect reported by people taking Tykerb in clinical trials. This side effect was common regardless of whether people took Tykerb with either Xeloda (capecitabine) or Femara (letrozole).
A rash caused by Tykerb is typically mild. Rarely, a rash can be a symptom of a more serious side effect, such as a severe skin reaction or an allergic reaction. (Learn more about these serious side effects below.)
What you can do
If you develop a rash while taking Tykerb, contact your doctor right away. This is important because a rash can be a symptom of a serious side effect. Your doctor will examine your rash and then determine how to treat it or whether you should stop Tykerb treatment.
Hand-foot syndrome
Taking Tykerb with Xeloda (capecitabine) can cause hand-foot syndrome. This condition involves redness, blistering, and swelling that affects your hands and feet. It may also cause symptoms such as:
- numbness, tingling, burning, or itching
- discomfort
- tenderness
- rash
- trouble walking or using your hands
Symptoms of hand-foot syndrome are most likely to affect your hands and/or feet, but they may occur in other areas of your body.
In people who took Tykerb with Xeloda in clinical trials, hand-foot syndrome was a common side effect. It’s important to note that hand-foot syndrome is a known side effect of Xeloda. People who took Tykerb with the drug Femara (letrozole) did not report hand-foot syndrome as a side effect.
What you can do
To help prevent hand-foot syndrome while taking Tykerb, avoid or minimize exposing your hands and feet to heat. You should also avoid squeezing your hands and putting pressure on your feet. Don’t use hand tools, such as screwdrivers.
Your doctor may also recommend that you do not exercise while you’re taking Tykerb. Or, they may recommend forms of exercise that don’t strain your hands or feet.
If you notice redness, blistering, and/or swelling affecting your hands and feet while taking Tykerb, contact your doctor. They may recommend managing your symptoms by:
- applying an ice pack or cold compress to affected areas
- keeping your hands and feet elevated (raised above chest level) when sitting or lying down, when possible
- patting your skin dry after showering or being in water, instead of rubbing
- avoiding shoes that are too small or rub against your feet
- using mild skin creams to keep your hands and feet moisturized
Serious skin reactions
Although very rare, people taking Tykerb in clinical trials reported severe skin reactions. Examples of these reactions include Stevens-Johnson syndrome and toxic epidermal necrolysis.
Symptoms of severe skin reactions caused by Tykerb can include:
- blistering of your eyes, lips, or mouth
- fever
- a rash or reddened skin
- skin peeling
What you can do
If you develop any of the above symptoms, contact your doctor right away. Although rare, these reactions can be life-threatening. People with severe skin reactions will require treatment in the hospital. And, your doctor will have you stop taking Tykerb if you develop a severe skin reaction. They’ll recommend a different treatment for your cancer instead.
Allergic reaction
As with most drugs, Tykerb can cause an allergic reaction in some people. But this side effect wasn’t reported in clinical studies.
Symptoms can be mild or serious and can include:
- rash
- itching
- flushing (temporary warmth, redness, or deepening of skin color)
- swelling under your skin, typically in your lips, eyelids, feet, or hands
- swelling of your mouth, tongue, or throat, which can make it hard to breathe
What you can do
For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Tykerb. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.
Be sure to talk with your doctor about your health history before you take Tykerb. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health.
Boxed warning: Severe liver damage
This drug has a
Other precautions
In addition to the boxed warning described above, other conditions and factors to consider before you take Tykerb include:
Heart disease or heart problems. If you have heart problems such as heart disease, you may not be able to take Tykerb. This is because Tykerb can cause side effects that affect your heart. For example, it may cause your heart to pump blood less effectively. It can also cause an irregular heartbeat.
Before you take Tykerb, your doctor will check your heart health using imaging tests. Your doctor will discuss your heart condition with you and how Tykerb may affect it. And if your doctor prescribes Tykerb for you, they’ll continue to check your heart health during treatment.
Low blood levels of magnesium or potassium. Although rare, taking Tykerb can affect your heart rhythm. If you have low blood levels of magnesium or potassium, you may be at higher risk for heart rhythm problems with Tykerb. Be sure your doctor is aware of any magnesium or potassium problems you have before you start taking Tykerb. They may want to treat these problems first.
Allergic reaction. You shouldn’t take Tykerb if you’ve ever had an allergic reaction to Tykerb or any of its ingredients. Talk with your doctor about which other treatments are better choices for you.
Alcohol use with Tykerb
Alcohol isn’t known to interact with Tykerb. But drinking alcohol could worsen certain side effects of Tykerb, such as diarrhea. Alcohol use may also increase your risk for liver problems since both alcohol and Tykerb can cause this.
If you drink alcohol, ask your doctor how much alcohol is safe for you to have while taking Tykerb.
Pregnancy and breastfeeding while taking Tykerb
You shouldn’t use Tykerb while pregnant or breastfeeding. You should also avoid breastfeeding for 1 week after your last dose of the drug. Although it isn’t known whether the drug may pass into breast milk, animal studies have shown that Tykerb may cause fetal harm.
If you can become pregnant, your doctor will likely have you take a pregnancy test before prescribing Tykerb. This is to confirm that you aren’t pregnant before you start taking the medication. You’ll also need to use an effective form of birth control while taking Tykerb and for at least 1 week after your last dose.
Tykerb can cause some side effects, most of which are mild and go away without medical help. But you should talk with your doctor if you have symptoms of serious side effects while taking Tykerb. You should also talk with your doctor if you become pregnant while taking Tykerb.
If you’d like to learn more about Tykerb, contact your doctor or pharmacist. They can help answer any questions you have about side effects of the drug.
Besides talking with a health professional, you can do some research on your own. These articles might help:
- More information on Tykerb. For details on other aspects of Tykerb, refer to this article.
- A look at breast cancer. For more information on breast cancer, see our list of breast cancer articles.
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.