This medication is used to treat a certain type of leukemia (CD33-positive acute myeloid leukemia-AML). This medication works by slowing or stopping the growth of cancer cells.

This medication is given by slow injection into a vein as directed by your doctor, usually over 2 hours. The dosage and treatment schedule are based on your medical condition, response to treatment, and body size.

Infusion reactions may happen during the infusion of this drug and for up to 24 hours afterward. Your doctor may prescribe other medications (such as acetaminophen, diphenhydramine) before each treatment to help prevent these side effects. Tell your doctor right away if you have any symptoms of infusion reactions such as chills, fever, fast heartbeat, shortness of breath, or dizziness. Your doctor may give you other medications to help with these side effects or may slow down or stop your treatment for some time.

To get the most benefit from this medication, do not miss any doses. To help you remember, mark your calendar with a reminder.

See also Warning and How to Use sections.

Nausea, vomiting, constipation, or headache may occur. Pain or sores in the mouth and throat may occur. Brush your teeth carefully/gently, avoid using mouthwash that contains alcohol, and rinse your mouth often with cool water mixed with baking soda or salt. It may also be best to eat soft, moist foods. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.

This medication may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infection (such as sore throat that doesn't go away, fever, chills, cough).

Tell your doctor right away if you have any serious side effects, including:

• easy bruising/bleeding

Get medical help right away if you have any very serious side effects, including:

• fast/irregular heartbeat
• severe dizziness
• signs of bleeding (such as pink/bloody urine, dark/tarry stools, vomit that looks like coffee grounds)
• symptoms of bleeding in the brain (such as dizziness/fainting, sudden vision changes, nausea, seizures, confusion)

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• other blood/bone marrow disorders (such as increased white blood cell count)
• bone marrow transplant
• liver disease
• recent/current infection

This medication can make you more likely to get infections or may make current infections worse. Stay away from anyone who has an infection that may easily spread (such as chickenpox, COVID-19, measles, flu). Talk to your doctor if you have been exposed to an infection or for more details.

Tell your health care professional that you are using gemtuzumab ozogamicin before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.

This medication may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using gemtuzumab ozogamicin, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions:

• certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG)
• family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death)

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using this medication safely.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above).

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using this medication. Gemtuzumab ozogamicin may harm an unborn baby. Women using this medication should ask about reliable forms of birth control during treatment and for at least 6 months after the last dose. Men using this medication should ask about reliable forms of birth control during treatment and for at least 3 months after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this drug and for at least 1 month after the last dose. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as complete blood count, liver function) should be done while you are using this medication. Keep all medical and lab appointments.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Not applicable. This medication is given in a hospital or clinic and will not be stored at home.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).