If you have a certain kind of cancer, your doctor might suggest Mylotarg as a treatment option. It’s a prescription drug used to treat acute myeloid leukemia (AML) in adults and some children.

Specifically, Mylotarg is used in:

  • adults and children ages 1 month and older with a new diagnosis of CD33-positive* AML
  • adults and children ages 2 years and older who have relapsed or refractory CD33-positive AML

* “CD33-positive” means the cancer cells have a high level of the protein CD33 on their surface.

Mylotarg is not a long-term treatment. How long your treatment lasts will depend on several factors, such as the kind of AML you have and the treatment plan your doctor prescribes.

Mylotarg comes as a liquid solution that’s given by a healthcare professional as an intravenous (IV) infusion. (This is an injection into your vein given over a period of time.)

The active ingredient in Mylotarg is gemtuzumab ozogamicin. (An active ingredient is what makes a drug work.) Mylotarg is a biologic drug that only comes in a brand-name form. Biologics are made from parts of living cells. Mylotarg is not available in a biosimilar form. (Biosimilars are like generic drugs. But unlike generics, which are made for non-biologic drugs, biosimilars are made for biologic drugs.)

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

Like other drugs, Mylotarg can cause mild to serious side effects. Keep reading to learn more.

Some people may experience mild to serious side effects during their Mylotarg treatment. Examples of commonly reported side effects include:

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

These are only a few of the side effects you might have with Mylotarg. Keep reading to learn about others that are possible with this drug.

Mylotarg may cause mild side effects. Examples that have been reported with this drug include:

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop Mylotarg treatment unless your doctor recommends it.

Mylotarg 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 Mylotarg, visit MedWatch.

Serious side effects are common with Mylotarg.

Serious side effects that have been reported with this drug include:

* To learn more about this side effect, see the “Side effects explained” section below.
Mylotarg 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 develop serious side effects while taking Mylotarg, 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.

Learn more about some of the side effects Mylotarg may cause.

Liver problems

Mylotarg has a boxed warning for the risk of liver problems. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about severe side effects of a drug.

In studies, liver problems were a common side effect of Mylotarg. Some people developed a life threatening condition called veno-occlusive disease (VOD). This happens when there is a blockage in the veins in the liver that prevents blood from flowing through it. Without enough blood, the liver can become damaged.

Symptoms of VOD include:

People with certain risk factors for liver problems may be more prone to this side effect of Mylotarg. Risk factors include:

What might help

Talk with your doctor immediately if you notice symptoms of liver disease, such as dark-colored urine, yellow skin, or weight gain.

Your doctor will check your liver function before prescribing Mylotarg and before you receive each dose. And they’ll continue to check your liver function throughout your treatment cycles. If the results of your liver function tests are abnormal, your doctor may still recommend Mylotarg, but you’ll need to test your liver function more often.

To manage symptoms of liver problems, your doctor may have you stop your Mylotarg treatment temporarily or permanently. They may also give you other treatments to manage the symptoms of VOD.


Infections were a common side effect of Mylotarg in studies of the drug. Mylotarg can reduce the activity of your immune system, which causes an increased risk of infection.

Reported infections from Mylotarg include fungal and bacterial infections, some of which were serious. And adults ages 65 years and older were more likely to experience this side effect.

Symptoms of an infection depend on the kind of infection you have and include:

What might help

Since Mylotarg can reduce the number of immune cells in your blood, your doctor will check your blood often. If you think you have an infection, talk with them immediately.

A few tips to help prevent infection include:

  • washing your hands often
  • staying away from people who are ill
  • following food safety guidelines


The active ingredient in Mylotarg is gemtuzumab ozogamicin, which is an antibody drug. It decreases the production of blood cells. These include platelets, a kind of blood cell that helps your blood clot. By reducing the platelet count in your blood, Mylotarg can increase the risk of certain kinds of bleeding.

In studies, bleeding was occasionally very serious, especially if it occurred in the brain or head. Symptoms vary depending on the location of the bleed.

If you have a bleed in your brain, you may have:

If the bleeding is in your lungs, you may have:

Bleeding in your stomach can cause nonspecific symptoms such as:

What might help

Your doctor will check your platelet count before you start Mylotarg and often throughout your treatment. They’ll also check you for signs and symptoms of bleeding. If you have severe bleeding, your doctor may delay your next dose or have you stop Mylotarg completely.

Report any symptoms of bleeding to your doctor immediately. And be sure to talk with them if you’re concerned about this side effect.

Febrile neutropenia

Febrile neutropenia was a common and serious side effect of Mylotarg in studies. Neutropenia happens when the level of neutrophils, a type of immune cell found in your blood, decreases. Having fewer neutrophils can put you at risk of infection. And if the level of these cells gets too low, your infection can be serious. Febrile neutropenia happens when you have neutropenia and a fever higher than 100.3°F.

What might help

Your doctor will check your blood often before and during treatment with Mylotarg. If you have a fever with Mylotarg, tell your doctor immediately. They may order more blood tests and possibly other tests, such as X-rays and a urine test.

Your doctor may not find the exact cause of your fever. Regardless, you’ll receive antibiotics by intravenous (IV) infusion (an injection into your vein given over time). You may require hospitalization and close monitoring by your healthcare team.

Infusion reactions

An infusion reaction is a potentially severe type of allergic reaction that is common with antibody drugs. (Mylotarg contains the active ingredient gemtuzumab ozogamicin, which is an antibody drug.)

In studies, infusion reactions occurred during Mylotarg injection and up to 24 hours afterward.

Symptoms of infusion reactions can be life threatening and include:

What might help

To prevent infusion reaction from Mylotarg, your doctor will prescribe other medications. You’ll receive Tylenol (acetaminophen), a steroid, and Benadryl (diphenhydramine) before each infusion.

While receiving your infusion and for an hour afterward, a healthcare professional will closely monitor you for signs of infusion reaction.

If you have a severe infusion reaction to Mylotarg, your doctor will stop the infusion. Then, you’ll receive a steroid drug or another allergy medication such as diphenhydramine. Depending on how severe your reaction is, your doctor may have you stop Mylotarg altogether.

Allergic reaction

Like most drugs, Mylotarg can cause an allergic reaction in some people. Symptoms can be mild to 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

A serious allergic reaction called an infusion reaction is common with Mylotarg. (For more information, see “Infusion reactions” just above.)

What might help

Call your doctor right away if you have mild allergic reaction symptoms, such as a mild rash, after receiving your infusion and returning home. They may suggest a treatment to manage your symptoms. Examples include:

  • an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine)
  • a topical product, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Mylotarg, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic 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’ve had a serious allergic reaction to Mylotarg, they may have you switch to a different treatment.

Keeping track of side effects

During your Mylotarg treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful 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 the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Mylotarg affects you. They can then use this information to adjust your treatment plan if needed.

Mylotarg comes with several warnings, including a boxed warning.

Boxed warning: Risk of liver problems

Mylotarg has a boxed warning for the risk of liver problems. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). This includes severe or fatal veno-occlusive disease (VOD), in which blood flow in the liver decreases, which can cause liver damage.

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

Other warnings

Mylotarg 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 Mylotarg. The list below includes factors to consider.

Long QT syndrome. Mylotarg can affect how your heart beats and can cause a condition called long QT syndrome. This serious side effect is a change in heart rhythm. If you have a history of long QT syndrome or are taking other medications that can affect your heart rhythm, tell your doctor before starting Mylotarg. They’ll check your heartbeat with an electrocardiogram and may also check the electrolytes (essential minerals) in your blood. If necessary, you may need to repeat these tests during your treatment.

Low blood cell counts. With acute myeloid leukemia (AML), you may have low numbers of certain blood cells. Mylotarg can lower these numbers even more, which can increase your risk of infection and bleeding. Some symptoms of an infection may include fever, chills, and trouble breathing. Depending on the kind of infection you have, your symptoms might be different. (For example, symptoms will differ if you have a bleed in your head, stomach, or lungs.) Tell your doctor or seek emergency treatment immediately if you have bruising, a severe headache, or trouble breathing. Your doctor will tell you about other symptoms of bleeding you might have with Mylotarg. If you have low blood cell counts with Mylotarg, your doctor will check your blood frequently and might delay your next dose if needed. And they may have you stop Mylotarg treatment completely if your blood cell counts are too low.

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

AML with adverse-risk cytogenetics. People with AML will have bone marrow biopsies to check for abnormal cells and genes. This information helps doctors determine their outlook. If your test results show a complication called adverse-risk cytogenetics, Mylotarg may not be the right treatment for you. If you’re taking other chemotherapy drugs for AML, your doctor will decide if the benefits of taking Mylotarg for your condition outweigh the risks.

Alcohol and Mylotarg

Although some medications interact with alcohol, Mylotarg isn’t one of them. But Mylotarg can cause nausea and vomiting, and alcohol may make this side effect worse. Also, Mylotarg has a boxed warning for risk of liver problems, and alcohol can also affect your liver.

Before starting Mylotarg, ask your doctor or pharmacist if it’s safe for you to drink alcohol. They may ask you questions about how much and what kinds you drink. If you can drink alcohol with Mylotarg, they’ll tell you how much is safe.

Pregnancy and breastfeeding with Mylotarg

Mylotarg is not safe to use during pregnancy, as it can harm a fetus. Before prescribing Mylotarg, your doctor will ask you to take a pregnancy test to confirm that you’re not pregnant. They will recommend using contraception throughout your treatment and for 3 to 6 months after your last dose of Mylotarg.

It’s not known if this drug passes through breast milk and, if it does, how this exposure might harm a breastfed child. It’s recommended that you do not breastfeed during Mylotarg treatment and for up to 1 month after your last dose.

If you’re pregnant or breastfeeding, talk with your doctor about the risks of Mylotarg.

Side effects are common with Mylotarg, and some can be serious. (To learn more about the possible severe side effects of this drug, see “What are the serious side effects of Mylotarg?” above.)

Talk with your doctor before starting Mylotarg treatment. Ask questions to help you feel more comfortable about side effects the drug may cause. Some examples to get you started are:


Does Mylotarg cause weight gain?



Mylotarg does not cause weight gain. A change in weight was not a side effect of Mylotarg in studies. But there are other factors to consider. This drug can cause a loss of appetite, nausea, and vomiting, which can lead to weight loss. But it can also cause liver problems, and with liver failure, you might quickly gain weight.

If you notice changes in your weight during Mylotarg treatment, tell your doctor before your next dose. They can help determine the cause, and they’ll need your current weight to calculate your dose.

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.