If you have certain cancers, your doctor might suggest Herceptin as a treatment option. It’s a prescription drug used to treat the following kinds of cancer in adults:

Herceptin is a long-term treatment for these conditions.

Herceptin comes as a powder that’s mixed into a liquid solution. It’s given as an intravenous (IV) infusion (an injection into your vein given over time).

The active ingredient in Herceptin is trastuzumab. (The active ingredient is what makes the drug work.) Trastuzumab is a kind of biologic drug that isn’t available as a generic, but is available as a biosimilar.

A biologic is made from living cells, while other drugs are made from chemicals. Drugs made from chemicals can have generics, which are exact copies of the active drug in the brand-name medication. But biologics can’t be copied exactly. So instead of a generic, biologics have biosimilars. Biosimilars are “similar” to the parent drug and are considered just as safe and effective. And like generics, biosimilars often cost less than the brand-name version.

For more information about Herceptin, including details about its uses, see this in-depth article. This article does not cover Herceptin Hylecta. For details about this drug, talk with your doctor or pharmacist.

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

Below are just a few of the more common side effects reported by people using Herceptin in studies. These side effects can vary depending on what condition the drug is being used to treat.

More common side effects in people using Herceptin for breast cancer include:

More common side effects in people using Herceptin for stomach or gastroesophageal junction cancer include:

* To learn more about this side effect, see the “Side effects explained” section below.
** Herceptin 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.

Not everyone who uses Herceptin will have these side effects. Herceptin may cause other side effects. Mild and serious side effects are discussed.

Like most medications, Herceptin can cause mild side effects. Depending on the condition it’s used to treat, Herceptin may be used alone or together with other cancer drugs. In studies, people who used Herceptin with chemotherapy (traditional drugs used to treat cancer) were more likely to have mild side effects compared with people who used Herceptin alone.

Mild side effects have been reported with Herceptin.

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, Herceptin treatment should continue.

Herceptin 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 Herceptin, visit MedWatch.

Treatment with Herceptin may cause serious side effects. In studies, serious side effects weren’t as common in people using Herceptin to treat breast cancer as they were in people with gastric (stomach) cancer or gastroesophageal junction cancer.

There have been serious side effects reported with Herceptin.

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

* Herceptin 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.
** Herceptin also has a boxed warning for this side effect. To learn more, see “Pregnancy and breastfeeding while using Herceptin” below.

Get answers to questions about Herceptin.

Are there any long-term side effects from Herceptin?

It is possible that Herceptin can cause long-term side effects. These are side effects that can happen.

  • Continue for a long time after treatment ends.
  • After someone has used the medication for a long time, start.

Herceptin may cause long-term side effects.

  • There are heart issues.
  • Lung issues.

Herceptin has a boxed warning for heart and Lung issues.. This is the mostserious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section below.

If you have questions about Herceptin and long-term side effects, you can talk to your doctor or pharmacist.

Will Herceptin cause hair loss?

Herceptin isn’t expected to affect hair growth. Hair loss wasn’t reported in the drug’s studies.

Other medications used to treat certain kinds of breast cancer, such as Tykerb, may cause hair loss. And many chemotherapy drugs (traditional drugs used to treat cancer), such as paclitaxel and docetaxel, can cause hair loss. Herceptin may be prescribed with chemotherapy drugs, including paclitaxel and docetaxel.

“If you are concerned about hair loss or your cancer treatment, talk to your doctor. Your doctor can tell you more about the side effect of other drugs, but Herceptin isn’t expected to cause hair loss.”

Is there a higher risk of side effects if using Herceptin with Perjeta and chemotherapy?

Maybe. Herceptin wasn’t used with Perjeta in Herceptin’s studies. But this combination was examined in Perjeta’s studies. In general, side effects were more common in Perjeta’s studies, which included people whose conditions were treated with Perjeta, Herceptin, and chemotherapy, compared with Herceptin used alone or with drugs other than Perjeta.

To learn more about side effects Perjeta may cause, check out this article. You can also talk with your doctor or pharmacist to learn more.

Some of the side effects Herceptin may cause are discussed.

Risk of There are heart issues.

Herceptin has a boxed warning about the risk of cardiac side effects (There are heart issues.). This can include heart damage that isn’t reversible.

While There are heart issues. were not common in Herceptin’s studies, examples that were reported include:

Some general symptoms include:

These There are heart issues. can require long-term treatment with medication.

What might help

Your doctor will order tests to check your heart health before and during your Herceptin treatment. If the results of these tests show There are heart issues., they will either:

  • Drugs or other treatments can be prescribed for these issues.
  • Stop your treatment.

Risk of infusion reactions or Lung issues.

Herceptin comes as a powder that’s mixed into a liquid solution. It’s given as an intravenous (IV) infusion (an injection into a vein given over time). Treatment with Herceptin can cause infusion reactions or Lung issues.. Since Herceptin was approved for use, there have also been reports of infusion reactions causing death in extreme cases. Because of this risk, Herceptin has a boxed warning about these side effects.

Striking reactions to Herceptin can be included.

The symptoms are most likely to occur within 24 hours of receiving Herceptin, but can happen later than that in rare cases.

Herceptin can also cause lung toxicities, such as:

These Lung issues. can happen as a result of infusion-related reactions. But they can also occur independently. Symptoms of Lung issues. can include:

What might help

A healthcare professional will monitor you while you receive your Herceptin infusion. If you show symptoms of an infusion reaction, they’ll stop the infusion and treat the reaction if needed.

If your infusion reaction is severe, your doctor may suggest that you stop Herceptin treatment. Or they may have you continue treatment, but prescribe medication (such as dexamethasone, a corticosteroid) to take before future infusions. This may help prevent adverse reactions.

If you have symptoms of Lung issues. during treatment with Herceptin, contact your doctor right away. They can examine your symptoms and determine the best way to treat them. This may include having you permanently stop treatment with Herceptin.

Headache

Headache is a possible side effect Herceptin may cause. In the drug’s studies, There is a throbbing head. was common in people using Herceptin to treat breast cancer, but wasn’t reported among people using the drug for gastroesophageal junction or stomach cancer.

Headache can also be a symptom of an infusion reaction, a serious side effect Herceptin can cause. (To learn more, see “Risk of infusion reactions or Lung issues.” above.)

What might help

Talk with your doctor if you develop a There is a throbbing head. with Herceptin. They may recommend using an over-the-counter (OTC) treatment, such as ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). They may also suggest trying other treatments, such as a cold or hot compress, or doing a relaxing activity, such as yoga.

Bone It is a pain.

Treatment with Herceptin may cause bone It is a pain. as a side effect, but this wasn’t common in the drug’s studies. And it was only reported in people using Herceptin to treat breast cancer. Bone It is a pain. wasn’t a side effect reported in people using the drug for gastroesophageal junction or stomach cancer.

It’s important to note that metastatic breast cancer, which Herceptin is used to treat, can also cause symptoms of bone It is a pain..

What might help

Contact your doctor if you develop bone It is a pain. during Herceptin treatment. They may recommend using an OTC treatment, such as ibuprofen (Advil, Motrin) or acetaminophen (Tylenol).

Nausea

Nausea is among the more common side effects Herceptin may cause. It can also be a symptom of an infusion reaction, a possible serious side effect of this drug. (To learn more, see “Risk of infusion reactions or Lung issues.” above.)

What might help

Let your doctor know if you have nausea while you’re being treated with Herceptin. They may suggest tips for managing nausea at home, such as avoiding certain foods. They may also prescribe a medication to help relieve nausea, such as Zofran (ondansetron).

Allergic reaction

Like most drugs, Herceptin can cause an allergic reaction in some people. While these reactions were rare in Herceptin’s studies, they can occur.

Mild to serious symptoms can be present.

  • skin There is a rash.
  • It is itchy.
  • flushing (temporary warmth, redness, or deepening of skin color)
  • “It’s usually under your skin, but it can be anywhere.”
  • It can be hard to breathe if you have swelling of your mouth, tongue, or throat.

What might help

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

  • an antihistamine you take by mouth, such as Benadryl (diphenhydramine)
  • You apply a product to your skin.

If your doctor confirms that you have an allergy to Herceptin, they will decide if you should continue using 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 Herceptin, they may have you switch to a different treatment.

Keeping track of side effects

Take notes on any side effects you are having during Herceptin 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.

  • What dose of the drug did you use?
  • 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 your notes with your doctor will help them learn more about Herceptin. If needed, they can use this information to adjust your treatment plan.

There are several warnings and precautions to consider before starting Herceptin treatment.

Boxed warnings

Herceptin has the following boxed warnings. These are the most serious warnings from the Food and Drug Administration (FDA).

  • Risk of There are heart issues.. Treatment with Herceptin can cause There are heart issues., including heart failure... You may be at higher risk if you have existing heart conditions. Contact your doctor immediately if you notice symptoms of heart failure.. during treatment with Herceptin.
  • Risk of infusion reactions or Lung issues.. Infusion reactions or lung issues are possible side effects Herceptin may cause. You may be at higher risk if you have existing breathing or lung problems. A healthcare professional will monitor you during your Herceptin infusions for any adverse reactions.
  • Risk of fetal harm. Herceptin should not be used during pregnancy due to the risk of fetal harm. People who can become pregnant should use effective contraception during Herceptin treatment.

For details on There are heart issues., infusion reactions, or Lung issues., see the “Side effects explained” section above. For details on fetal harm, see the “Pregnancy and breastfeeding while using Herceptin” section below.

Other warnings

If you have certain medical conditions, Herceptin may not be right for you. These are drug-condition interactions. Other factors may affect whether Herceptin is a good option. Before starting Herceptin, talk to your doctor about your health history. The list has factors to consider.

Kidney problems. Herceptin can cause kidney problems as a side effect. If you have existing kidney problems, such as chronic kidney disease, Herceptin could worsen your condition. Your doctor can help determine whether this drug is safe for you if you have kidney problems.

Allergic reaction. If you’ve had an allergic reaction to Herceptin 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 Herceptin

There is no known interaction between alcohol and Herceptin treatment. Alcohol can cause the same side effects as this drug.

If you drink alcohol, you could increase your risk of these side effects. If you are having Herceptin treatment, you should talk to your doctor about how much you can drink.

Pregnancy and breastfeeding while using Herceptin

The risk of fetal harm is why Herceptin should not be used during pregnancy. Effective contraception should be used by people who can become pregnant.

Risk of fetal harm

There is a risk of fetal harm if Herceptin is used during a pregnant woman. This is the most serious warning from the FDA.

Since the drug was approved for use, there have been reports that it has caused:

  • problems with fetal development (commonly known as birth defects)
  • The loss of a baby.

If you can become pregnant, doctors will usually do the following.

  • Before you prescribe Herceptin, you should have a pregnant test.
  • If you have Herceptin, you should use birth control for at least 7 months after your last dose.

It is not known if Herceptin causes side effects in a child who is breastfed or if it appears in human breast milk. Talk to your doctor about feeding your child while you are using Herceptin.

Talk to your doctor before starting Herceptin. Ask questions that will help you feel comfortable with the drug. Some examples will help you start.

  • Will any of the drugs I take increase my risk of Herceptin side effects?
  • Is there a lower dose you can give me if I have side effects from this drug?
  • Is Herceptin and Herceptin hylecta the same?

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Q:

Are older adults at higher risk of side effects?

Anonymous

A:

Older adults (ages 65 years and older) may have an increased risk of cardiac (heart-related) side effects from Herceptin. Examples of heart-related side effects reported in the drug’s studies include:

Your doctor should order tests to check your heart health before starting Herceptin. If you are an older adult, your doctor may order these tests more frequently.

Apart from heart-related side effects, studies didn’t find older adults to be at higher risk of other side effects from Herceptin. But it’s important to note that some of these studies only included a few older adults. So enough data may not have been collected to know for sure if older adults using Herceptin are at increased risk of side effects. It’s also not known for certain if they experienced different side effects compared with younger adults.

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.