If you have certain forms of breast cancer, your doctor might suggest Kadcyla (ado-trastuzumab emtansine) as a treatment option. It’s a prescription drug used to treat HER2-positive (HER2+) breast cancer in adults in certain situations.
The active ingredient in Kadcyla is ado-trastuzumab emtansine (also called T-DM1). Kadcyla is a kind of
Kadcyla is given by a healthcare professional as an intravenous (IV) infusion. This is an injection into your vein given over time.
For more information about Kadcyla, including details about its uses, see this in-depth article on the drug.
Like other drugs, Kadcyla can cause mild or serious side effects. Keep reading to learn more.
Some people may experience mild or serious side effects during Kadcyla treatment.
Examples of Kadcyla’s commonly reported side effects include:
- fatigue (low energy)
- nausea
- muscle pain
- bone pain
- hemorrhage (severe bleeding inside the body)
- headache
These aren’t the only side effects Kadcyla may cause. To learn more, see the following sections.
Like most medications, treatment with Kadcyla can cause mild side effects. Examples of mild side effects that have been reported include:
- pain in bones, joints, or muscles
- nosebleed
- constipation
- diarrhea
- dry mouth
- fever
- headache
- fatigue (low energy)
- mouth sores
- nausea
- weakness
- vomiting
- blurred vision*
- stomach pain*
* To learn more about this side effect, see the “Side effects explained” section below.
In most cases, these side effects should be temporary. And some may be manageable, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And do not stop Kadcyla treatment unless your doctor recommends this.
Kadcyla may cause mild side effects other than the ones listed above. See the Kadcyla 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 Kadcyla, visit MedWatch.
Serious side effects are possible with Kadcyla. Some of these are more common than others. Certain factors may also affect your risk of serious side effects.
Serious side effects that have been reported with Kadcyla include:
- extravasation (symptoms that occur due to the drug leaking into tissue around your vein after injection), which may cause pain and swelling
- infusion reaction (side effects that happen during or soon after a Kadcyla infusion)*
- low platelet level, which can raise your risk of hemorrhage (severe bleeding inside the body)
- lung problems, including interstitial lung disease (conditions that affect lung tissue)
- nerve damage, which may cause numbness, tingling, or weakness in the hands or feet
- hemorrhage
- risk of serious liver problems**
- risk of serious heart problems**
- risk of fetal harm if taken during pregnancy†
- allergic reaction‡
If you develop serious side effects while receiving Kadcyla, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.
* To learn more about this side effect, see the “Ask a pharmacist” section at the end of this article.
** Kadcyla has a
† Kadcyla has a boxed warning for this side effect. To learn more, see “Pregnancy and breastfeeding while receiving Kadcyla” in “Warnings for Kadcyla” below.
‡ To learn more about this side effect, see the “Side effects explained” section below.
Get answers to some frequently asked questions about Kadcyla’s side effects.
Can ado-trastuzumab emtansine (T-DM1), the active ingredient in Kadcyla, cause hair loss?
It’s not likely. Hair loss wasn’t reported by people receiving Kadcyla in studies.
Hair loss is a common side effect of some other breast cancer treatments. These include certain chemotherapy* drugs called taxanes, such as pacl*taxel. Taxanes are prescribed with Kadcyla to treat metastatic† breast cancer, and are known to cause hair loss. But this isn’t a known side effect of Kadcyla.
Talk with your doctor if you’re concerned about hair loss and breast cancer treatment. You can also check out these tips for preventing or managing hair loss caused by cancer treatment.
* Chemotherapy drugs are standard drugs used to treat cancer.
† Metastatic means the cancer has spread from the breast to other parts of the body.
Are the side effects of Kadcyla or T-DM1 similar to chemotherapy side effects?
Possibly. Kadcyla has some of the same side effects as standard chemotherapy drugs. These include nausea, diarrhea, and fatigue (low energy).
Kadcyla’s active ingredient consists of ado-trastuzumab that’s chemically linked to emtansine. Emtansine is a chemotherapy drug, and ado-trastuzumab is a monoclonal antibody. Monoclonal antibodies work differently than chemotherapy drugs to treat cancer.
Kadcyla is a targeted therapy that’s designed to target HER2-positive (HER2+) breast cancer cells. Targeting cancer cells can help prevent some side effects that traditional chemotherapy can cause.
Can Kadcyla cause long-term side effects?
Yes. Although it’s not common, Kadcyla can cause long-term side effects.
Long-term side effects are side effects that can occur even after you’ve taken a drug for a long time. It also includes side effects that may last a long time after the drug is stopped.
Long-term side effects reported with Kadcyla include:
- serious liver problems,* such as liver damage
- serious heart problems,* such as heart failure
- nerve damage
- hemorrhage (severe bleeding inside the body)
- lung problems, including interstitial lung disease (conditions that affect lung tissue)
Some of these side effects are discussed in the “Side effects explained” section just below. To learn more about Kadcyla and long-term side effects, you can also talk with your doctor or pharmacist.
* Kadcyla has a
Learn more about some of the side effects Kadcyla may cause.
Stomach pain
Stomach (belly) pain is a possible side effect of Kadcyla treatment. This side effect was somewhat common in studies. But it wasn’t among the more commonly reported side effects.
In most cases, stomach pain was mild or moderate and was not considered serious. But stomach pain can also be a symptom of severe liver problems. These are discussed just below in “Risk of serious liver problems.”
What might help
Contact your doctor right away if you notice stomach pain while you’re receiving Kadcyla. Your doctor will likely want to evaluate your symptoms to check for signs of liver damage.
If needed, your doctor might discuss treatment options with you. This may include prescribing a medication to reduce your stomach pain. It could also include having you temporarily or permanently stop Kadcyla.
Blurred vision
Blurred vision is a rare side effect of Kadcyla. This side effect wasn’t common in the drug’s studies.
What might help
Contact your doctor if you notice blurred vision during treatment with Kadcyla. They may suggest temporarily or permanently stopping Kadcyla.
Your doctor may also recommend that you avoid activities that could be dangerous while you’re having blurred vision. This might include driving or using heavy machinery. Be sure to follow your doctor’s instructions.
Risk of serious liver problems
Kadcyla has a
For most people in studies, liver problems occurred as changes in levels of liver enzymes (kinds of proteins), which didn’t cause any symptoms. But liver problems caused by Kadcyla can be severe and fatal.
Symptoms of liver problems can include:
- dark-colored urine
- itchy skin
- light-colored stool
- nausea and vomiting
- right upper belly pain
- jaundice (yellowing of your skin or the whites of your eyes)
Some people receiving Kadcyla in studies developed nodular regenerative hyperplasia, a rare liver condition.
It’s not known whether existing liver problems such as hepatitis (a kind of liver infection) will get worse with Kadcyla treatment. The drug’s studies didn’t include people who had known liver conditions.
What might help
Before you begin Kadcyla treatment, your doctor will likely order a blood test to check your liver enzyme levels. You’ll probably have this test from time to time during treatment. If your levels become too high, your doctor may lower your Kadcyla dose or have you permanently stop the drug.
You should contact your doctor right away if you notice symptoms of liver damage while you’re receiving treatment with Kadcyla. They’ll likely want to evaluate your symptoms. Be sure to talk with your doctor or pharmacist if you have questions about your risk of liver problems.
Risk of serious heart problems
Kadcyla has a
Symptoms of heart failure can include:
- cough
- dizziness
- loss of consciousness
- shortness of breath
- swelling in your ankles, feet, or lower legs
- unusually fast weight gain, such as gaining 5 pounds (about 2.3 kilograms) or more in 24 hours
What might help
Before prescribing Kadcyla, your doctor will evaluate your risk of heart problems. If they decide that treatment with Kadcyla is safe for you, they’ll monitor your heart health while you’re receiving the drug.
If there are any changes in your heart function, your doctor will likely have you temporarily stop Kadcyla to see if the side effect goes away. They’ll likely have you permanently stop Kadcyla if your heart function doesn’t return to usual or continues to get worse.
Allergic reaction
Like most drugs, Kadcyla can cause an allergic reaction in some people. This includes infusion reactions (side effects that occur during or soon after an infusion of Kadcyla). These reactions weren’t common in the drug’s studies.
Symptoms of an allergic reaction can be mild or serious and can include:
- skin rash
- itchiness
- flushing (temporary warmth, redness, or deepening of skin color)
- swelling under your skin, usually in your eyelids, lips, hands, or feet
- swelling of your mouth, tongue, or throat, which can make it hard to breathe
Symptoms of an infusion reaction can include:
- flushing
- chills
- fast heart rate
- trouble breathing
- fever
See the “Ask a Pharmacist” section below for more details about infusion reactions.
What might help
If you have mild symptoms of an allergic reaction or infusion reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter antihistamine that’s taken by mouth, such as Benadryl (diphenhydramine), to manage your symptoms. Or they might recommend a product that’s applied to the skin, such as hydrocortisone cream.
If your doctor confirms you had a mild reaction to Kadcyla, they’ll decide if you should continue receiving the drug.
If you have symptoms of a severe reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.
If your doctor confirms you had a serious allergic reaction or infusion reaction to Kadcyla, they may have you switch to a different treatment.
Keeping track of side effectsDuring Kadcyla treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.
Your side effect notes can include things such as:
- what dose of drug you were receiving when you had the side effect
- how soon after starting that dose you had the side effect
- what your symptoms were from the side effect
- how your symptoms affected your daily activities
- what other medications you were also taking
- any other information you feel is important
Keeping notes and sharing them with your doctor will help your doctor learn more about how Kadcyla affects you. And your doctor can use this information to adjust your treatment plan if needed.
Before starting treatment with Kadcyla, there are certain precautions for you and your doctor to consider. This includes several boxed warnings.
Boxed warnings
Kadcyla has several
- Risk of serious liver problems. Treatment with Kadcyla may raise your risk of serious liver problems. In rare cases, these can be fatal. To learn more, see “Side effects explained” above.
- Risk of serious heart problems. Kadcyla raises your risk of serious heart problems, including heart failure. To learn more, see “Side effects explained” above.
- Risk of fetal harm. Kadcyla can cause harm to a fetus if it’s taken during pregnancy. For details, see “Pregnancy and breastfeeding while receiving Kadcyla” below.
Other warnings
Kadcyla may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before starting Kadcyla. The list below includes factors to consider.
Bleeding problems. Treatment with Kadcyla can cause bleeding, including hemorrhage (severe bleeding inside the body). If you have a condition that increases your risk of bleeding, you may be at higher risk of bleeding with Kadcyla. Your doctor can help determine if Kadcyla is safe for you.
Breathing or lung problems. Kadcyla can cause lung problems, such as pneumonitis (swelling in your lungs). People who already have breathing or lung problems may be at higher risk of this side effect. Your doctor will determine if Kadcyla is safe for you.
Liver problems. Kadcyla can cause liver problems, including serious liver damage. If you already have liver problems, you may be at higher risk of this side effect. Your doctor can help determine if Kadcyla is safe for you.
Heart problems. Serious heart problems, including heart failure, can occur with Kadcyla. If you already have heart problems, your risk of this kind of side effect may be higher. You and your doctor will discuss whether Kadcyla treatment is safe for you.
Low blood platelet level. If you have a low level of platelets in your blood, you may be at higher risk of bleeding, including hemorrhage, with Kadcyla. You and your doctor will discuss whether Kadcyla treatment is safe for you.
Nerve problems. Nerve damage can occur with Kadcyla. If you have preexisting nerve damage, also called neuropathy, you may be at a higher risk of this side effect. You and your doctor will discuss whether Kadcyla treatment is safe for you.
Allergic reaction. If you’ve had an allergic reaction to Kadcyla or any of its ingredients, your doctor will likely not prescribe Kadcyla. Ask your doctor what other medications are better options for you.
Alcohol and Kadcyla
There aren’t any known interactions between alcohol and Kadcyla. But both alcohol and Kadcyla can cause liver problems. So drinking alcohol while you’re in Kadcyla treatment could increase your risk of liver problems or make existing liver problems worse. Keep in mind that Kadcyla has a
Talk with your doctor about how much alcohol, if any, is safe for you to drink while you’re receiving Kadcyla. For more information about Kadcyla and liver problems, see “Side effects explained” above.
Pregnancy and breastfeeding while receiving Kadcyla
You should not receive Kadcyla treatment while pregnant. Kadcyla has a
If you’re able to become pregnant, your doctor will have you take a pregnancy test to make sure you’re not pregnant before prescribing Kadcyla.
Females* should use birth control while receiving Kadcyla and for at least 7 months after their last dose. Males* with partners who are able to become pregnant should also use birth control while receiving Kadcyla and for at least 4 months after their last dose.
You should not breastfeed while receiving Kadcyla and for at least 7 months after your last dose. It’s not known whether Kadcyla passes into breast milk. But the drug could cause serious harm to a child who is breastfed. Talk with your doctor about healthy feeding options for your child.
You can also talk with your doctor if you have more questions about receiving Kadcyla during pregnancy or while breastfeeding.
If you’re exposed to Kadcyla during pregnancy or if you become pregnant within 7 months of your last dose of Kadcyla, talk with your doctor. You’re encouraged to report Kadcyla exposure to the Pregnancy Pharmacovigilance Program by calling 888-835-2555. This program helps healthcare professionals gather information about the safety of certain medications.
* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.
Treatment with Kadcyla can cause mild or serious side effects. Before you start Kadcyla treatment, talk with your doctor. Ask questions to help you feel comfortable with your decision about breast cancer treatment. Some examples to help get you started are:
- If I have side effects from Kadcyla, is there a lower dose I can try?
- Do other medications I take raise my risk of side effects from Kadcyla?
- How often will I need to have blood tests while I’m receiving Kadcyla?
For information on treatments and advice on managing your condition, sign up for Healthline’s breast cancer newsletter. And to connect with others living with breast cancer, consider joining the Bezzy BC community.
Q:
My doctor tells me I’ll get Kadcyla as an infusion. Can you tell me more about infusion reactions the drug can cause?
Anonymous
A:
Infusion reactions are a possible side effect of Kadcyla. Infusion reactions refer to side effects that occur when your immune system has a strong response to a drug that’s given as an intravenous (IV) infusion. This is an injection into your vein given over time.
These side effects can occur during or soon after an infusion. Your risk of a reaction is highest during your first Kadcyla infusion.
Infusion reactions reported with Kadcyla include:
- chills or fever
- flushing (temporary warmth, redness, or deepening of skin color)
- shortness of breath or wheezing (noisy breathing)
- fast heart rate
- low blood pressure
Your doctor or another healthcare professional will monitor you during each Kadcyla infusion. They can temporarily pause your infusion if you develop a reaction. Or they might slow down how quickly Kadcyla is infused into your vein.
In most cases, mild infusion reactions go away on their own a few hours or days after the infusion. Depending on your symptoms, you may need treatment. If you have a serious reaction, your doctor will likely have you permanently stop Kadcyla treatment.
The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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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.
