Before Using This Medicine

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

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to topotecan. Also tell your health care professional if you are allergic to any other substances.

Pregnancy—Tell your doctor if you are pregnant. Studies in rats and rabbits have shown that topotecan causes birth defects and deaths of the fetus, as well as problems in the mother.

Be sure that you have discussed this with your doctor before starting treatment with this medicine. It is best to use birth control while you are receiving topotecan. Also, tell your doctor right away if you think you have become pregnant during treatment.

Breast-feeding—It is not known whether topotecan passes into breast milk. However, because this medicine may cause serious side effects, breast-feeding is generally not recommended while you are receiving it.

Children—Topotecan has been studied in a limited number of children. One study showed that seriously low blood counts may be more likely to occur in children than in adults.

Older adults—This medicine has been tested in elderly patients and has not been shown to cause different side effects or problems in older people than it does in younger adults.

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 topotecan, it is especially important that your health care professional know if you are taking any of the following:

• Amphotericin B by injection (e.g., Fungizone) or
• Antithyroid agents (medicine for overactive thyroid) or
• Azathioprine (e.g., Imuran) or
• Chloramphenicol (e.g., Chloromycetin) or
• Colchicine or
• Flucytosine (e.g., Ancobon) or
• Ganciclovir (e.g., Cytovene) or
• Interferon (e.g., Intron A, Roferon-A) or
• Plicamycin (e.g., Mithracin) or
• Zidovudine (e.g., AZT, Retrovir) or
• If you have ever been treated with radiation or other cancer medicines—The risk of seriously low blood counts may be increased

• Azathioprine (e.g., Imuran) or
• Chlorambucil (e.g., Leukeran) or
• Corticosteroids (cortisone-like medicine) or
• Cyclosporine (e.g., Sandimmune) or
• Mercaptopurine (e.g., Purinethol) or
• Muromonab-CD3 (monoclonal antibody) (e.g., Orthoclone OKT3) or
• Tacrolimus (e.g., Prograf)—There may be an increased risk of infection because topotecan decreases your body's ability to fight it

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

• Chickenpox (including recent exposure) or
• Herpes zoster (shingles)—Topotecan may cause these conditions to get worse and spread to other parts of your body

• Infection—Topotecan may decrease your body's ability to fight an infection

• Kidney disease—Higher blood levels of topotecan can occur, which increases the risk of serious side effects