Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For gemtuzumab ozogamicin, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to gemtuzumab ozogamicin, anti-CD33 antibody, or calicheamicin derivatives. Also tell your doctor and pharmacist if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Gemtuzumab ozogamicin may cause harm to the fetus when administered during pregnancy. There are no adequate, well-controlled studies in pregnant women. You should avoid becoming pregnant while receiving gemtuzumab ozogamicin. However, this medicine may be needed in serious diseases or other situations that threaten the mother's life. Be sure you have discussed this with your doctor.

Breast-feeding—It is not known if gemtuzumab ozogamicin passes into the breast milk. However, due to potential serious side effects in nursing babies from gemtuzumab ozogamicin, a decision should be made whether to stop nursing or to stop the drug.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of gemtuzumab ozogamicin in children with use in other age groups.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of gemtuzumab ozogamicin in the elderly with use in other age groups. However, laboratory values associated with liver problems were observed more often in patients 60 years old or older.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking gemtuzumab ozogamicin, it is especially important that your doctor or pharmacist know if you are taking any of the following:

• Alpha interferons (e.g., Intron A, Roferon-A) or
• Amphotericin B by injection (e.g., Fungizone) or
• Antineoplastics, other (cancer medicine) or
• Antithyroid agents (medicine for overactive thyroid) or
• Azathioprine (e.g., Imuran) or
• Chloramphenicol (e.g., Chloromycetin) or
• Colchicine or
• Cyclophosphamide (e.g., Cytoxan) or
• Flucytosine (e.g., Ancoban) or
• Ganciclovir (e.g., Cytovene) or
• Mercaptopurine (e.g., Purinethol)
• Methotrexate (e.g., Rheumatrex)
• Plicamycin (e.g., Mithracin)
• Zidovudine (e.g., AZT, Retrovir)—Concurrent use of these agents with gemtuzumab ozogamicin increases the risk of infection

Other medical problems—The presence of other medical problems may affect the use of gemtuzumab ozogamicin. Make sure you tell your doctor if you have any other medical problems, especially:

• Chickenpox (including recent exposure) or
• Herpes zoster (shingles)—Risk of severe disease affecting other parts of the body

• High blood cell counts (peripheral blasts)—Risk of side effects increased by gemtuzumab ozogamicin

• Infection—Risk increased by gemtuzumab ozogamicin
• Liver disease—May be worsened by gemtuzumab ozogamicin
• Stem-cell transplant—Risk of side effects increased by gemtuzumab ozogamicin