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Topoisomerase Inhibitors for Chemotherapy


Topoisomerase I inhibitors

Generic NameBrand Name
irinotecanCamptosar, Hycamtin, Etopophos
topotecanCamptosar, Hycamtin, Etopophos

Topoisomerase II inhibitors

Generic NameBrand Name

Topoisomerase (say "toh-poh-eye-SAHM-uh-rays") inhibitors are chemotherapy medicines used to treat several types of cancers, including testicular cancer, leukemia, and some lung cancers.

How It Works

Topoisomerase inhibitors interfere with enzymes called topoisomerases. This affects the growth of cancer cells and causes them to die.

Why It Is Used

Topoisomerase inhibitors slow or stop the growth of cancer cells in the body.

Irinotecan is often used in combination with other chemotherapy drugs, making the other drugs more effective than they are by themselves.1

How Well It Works

Topoisomerase inhibitors are effective antitumor medicines. But the type and extent of a cancer determines how effectively these medicines slow or stop the growth of cancer cells in the body.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Callor other emergency services right away if you have:

  • Trouble breathing or tightness in your throat.
  • Swelling of your face, lips, tongue, or throat.
  • A fast heartbeat or sweating.

Call your doctor right away if you have:

  • Hives.
  • Fever, chills, body aches, or other flu symptoms.
  • Severe diarrhea with fever or stomach pain.
  • Unusual tiredness or weakness.
  • Black, tarry stools or blood in your stools.
  • Blood in your urine or painful urination (with fever or chills).
  • White patches or sores inside your mouth or on your lips, or other signs of infection.

Taking topoisomerase inhibitors can increase your chances of getting an infection, so do your best to stay away from sick people. It may also keep your blood from clotting normally, so be very careful when using sharp objects.

Common side effects of this medicine include:

Treatment with topoisomerase II inhibitors (such as etoposide) can increase your risk for getting acute myelogenous leukemia (AML).

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

These medicines can affect your blood cells and your liver function. Your doctor will check your blood cell counts and your liver function while you are taking these medicines.

Talk to your doctor before taking these medicines if you have an infection or kidney or liver disease. And let your doctor know if you have had shingles or chickenpox (or have recently been exposed to chickenpox).

You may not be able to get pregnant or father a child after taking these medicines. Discuss fertility with your doctor before starting treatment.

While you are taking this medicine, don't get any "live" vaccines. Also, stay away from anyone who has recently had a live vaccine.

Women taking this medicine may experience menopausal symptoms, including hot flashes and vaginal dryness.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

Do not use this medicine if you are pregnant, breast-feeding, or planning to get pregnant. If you need to use this medicine, talk to your doctor about how you can prevent pregnancy.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)Click here to view a form.(What is a PDF document?) to help you understand this medication.



  1. Libutti SK, et al. (2011). Cancer of the colon. In VT DeVita Jr. et al., eds., DeVita, Hellman and Rosenberg's Cancer: Principles and Practice of Oncology, 9th ed., pp. 1084–1126. Philadelphia: Lippincott Williams and Wilkins.


ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerChristopher G. Wood, MD, FACS - Urology, Oncology
Last RevisedJanuary 4, 2013

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