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Irinotecan (eye-rin-oh-tee-kan) (also known as Camptosar, CPT-11, irinotecan hydrochloride) is a chemotherapy drug used to treat colon or rectal cancer. It may also be used for other cancers.

With respect to colon or rectal cancer that has spread beyond the colorectum (metasticized), Irinotecan is used in combination with 5-FU and Leucovorin both before and after surgery. The combination is referred to as FOLFIRI. (For information about FOLFIRI, cilck here).

What Irinotecan Is

Irinotecan is a partly manmade drug which comes from an extract of a plant that grows in Asia called Campthotheca acuminata

According to the American Cancer Society, Irinotecan is thought to work by blocking the action of an enzyme in cells called topoisomerese I. Cells need this enzyme to keep their DNA in the proper shape when they are dividing into 2 cells. Blocking this enzyme leads to breaks in the DNA, which leads to cell death. Because cancer cells divide faster than normal cells, they are more likely than normal cells to be affected by irinotecan.

Before Taking This Medicine, Tell Your Doctor

Tell your doctor…

  • If you are allergic to any medicines, dyes, additives, or foods.
  • If you have ever had radiation therapy to the abdomen or pelvis, as this may put you at increased risk for lowered blood cell counts.
  • If you have ever had liver problems. This drug is cleared from the body mainly by the liver. Reduced liver function may result in more drug than expected staying in the body, which could lead to unwanted side effects. Your doctor may need to adjust your dose accordingly.
  • If you have inherited fructose intolerance. Irinotecan contains sorbitol.
  • If you have any other medical conditions such as kidney disease, heart disease, lung or breathing problems, diabetes, high blood pressure, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause problems with the fetus if taken at the time of conception or during pregnancy. Men and women who are taking this drug should use some kind of birth control during treatment. It is important to check with your doctor about what kinds of birth control can be used with this medicine. In pregnant women, treatment with this drug should be used only if the potential benefit to the mother outweighs the risk to the fetus.
  • If you are breast-feeding. While no studies have been done, this drug may pass into breast milk and affect the baby. Breast-feeding is not recommended during treatment with this drug.
  • If you think you might want to have children in the future. This drug may affect fertility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Irinotecan: Interactions With Other Drugs And Food

Interactions with other drugs

Irinotecan can interact with a number of drugs and supplements, which may either raise or lower the level of irinotecan in your blood. Tell your doctor if you are taking any of the following:

  • anti-depressant drugs nefazodone (Serzone), fluvoxamine (Luvox), fluoxetine (Prozac, Serafem)
  • antibiotics erythromycin, clarithromycin, and similar drugs
  • anti-fungal antibiotics such as ketoconazole and itraconazole
  • the anti-nausea drug aprepitant
  • certain blood pressure medicines such as diltiazem and verapamil
  • HIV drugs such as indinavir, ritonavir, amprenavir, fosamprenavir, nelfinavir, atazanavir, and others
  • anti-seizure drugs carbamazepine, phenobarbital, and phenytoin can make the body get rid of irinotecan faster
  • TB drugs rifampin and rifabutin
  • St. John's wort (an herbal dietary supplement)

Don't start or stop taking any drugs while you are on irinotecan without talking with your doctor first.

This drug can cause serious diarrhea. Try to avoid laxatives and stool softeners while taking this drug.

There may be more drugs that interact with irinotecan. Check with your doctor, nurse, or pharmacist about your other medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

Grapefruit or grapefruit juice may also change the level of this drug in your blood. Check with your doctor, nurse, or pharmacist about whether these or other foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How Is Irinotecan Taken Or Given?

Irinotecan is given by an infusion into a vein (IV) over 90 minutes.

It is usually given either once every 3 weeks, or weekly for 4 weeks followed by 2 weeks off.

The dose will depend on a number of factors, including the treatment schedule, your body size, your age and general health, your blood counts, how well your liver is working, whether you have had radiation to your abdomen/pelvis, and whether you have any side effects such as diarrhea.

Irinotecan: Precautions

Do not take any medications without first checking with your oncologist or nurse. (If you stop taking a medication prescribed by another doctor, let that doctor know.

Lowered platetlet count which can increase your risk of bleeding. Do not take aspirin, ibuprofen such as Mortin or Advil, products containing them, warafin (Coumadin), or vitamin E without checking with your doctor first. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

If you undergo surgery or other procedure, tell your doctor or dentist before hand that you are on Irinotecan.

Keep an anti nausea prescription filled and with you "just in case" so you can stop nausea quickly.

Do not get any vaccines during or after treatment without first checking with your doctor. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine.

Call your doctor if :

  • You have pain your belly and cannot move your bowels, especially if you also have bloating and loss of appetite.
  • You experience any unexpected symptoms, or they are worse than expected. 
  • You have a fever of 100.5 degrees F or higher.
  • You get a new or worsening cough or trouble breathing. It may be a rare lung side effect. 

NOTE: As a practical matter, if you experience chemotherapy related diarrhea,  it is usually advisable to start with an over-the-counter medication such as Immodium rather than a stronger medication. Stronger medications can lead to constipation, which then has to be treated. This can become a back and forth seesaw making you very uncomfortable in the process. (For information about dealing with constipation, click here.)

To make life easier, patient advocates suggest that patients carry Immodium or another over-the-counter anti-diarrheal medication "just in case." The odds are that if diarrhea happens, you won't be able to immediately get to a pharmacy or other store to get anti-diarrheal medication.  The sooner you start treating diarrhea, the sooner you are likely to get it under control. Uncontrolled diarrhea can leads to unnecessary complications - and feeling poorly to boot.

When taking Immodium, follow the instructions on the container. However, if the diarrhea is more like a watery liquid (not just loose bowels), experienced patient advocates have found that Immodium can be more effective if taken every two hours for 12 hours straight. It doesn't matter if the condition continues - one episode of watery diarrhea is enough to trigger the suggestion.  DO NOT take this suggestion without checking with your health care team first.

Irinotecan: Possible Side Effects

Immediate Side Effects (start wtihin 24 hours of infusion)

  • Early onset diarrhea.  Diarrhea which occurs during infusion or soon after is referred to as "early onset diarrhea" as compared to "late onset diarrhea" which is diarrhea which occurs later. It is not advisable to treat early onset diarrhea because it usually clears up on its own. Treating such diarrhea can lead to constipation.
  • Abdominal cramping (stomach pain) while the drug is being given
  • Mild sweating, wtihout or without feeling warm
  • Nausea/Vomiting.
  • Dizziness and/or trouble with eyesight. If you experience this side effect, do not drive or operate machinery while it continues.

Common Side Effects That Start Later

  • Diarrhea - Diarrhea must be treated immediately to prevent dehydration and other serious complications. In addition to an over the counter medication such as Imodium, it is advisable to get a prescription from  your doctor to have on hand in case you need something more effective to help control this side effect. That medication as prescribed as soon as ou notice anay loose stools.
  • Runny nose, increased salive, excess tears in the eyes, sweating, flushing and abdominal cramps (due to the fact that drug may affect part  of your nervous sytem that controls body secretions. This is known as cholinergic syndrome. Medications from your doctor can help control these symptoms.
  • Nausea/vomiting. As you will see if you click on the link, medication for nausea should always be kept on hand so you can take the medication on the first sign of nausea. Nausea can lead to vomiting which can lead to dehydration and complications.
  • Lowered white blood cell count with increased risk of infection. To learn how to avoid infection, click here.
  • Lowered platetlet count which can increase your risk of bleeding. Do not take aspirin, ibuprofen such as Mortin or Advil, products containing them, warafin (Coumadin), or vitamin E without checking with your doctor first. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.
  • Temporary hair thinning or loss, including face and body hair
  • Abdominal (belly) pain (cramping)
  • Loss of appetite
  • Fatigue

According to the American Cancer Society, the following symptoms are less common 

  • Cholinergic syndrome (may include runny nose, increased saliva, sweating, tearing in the eyes, flushing, abdominal cramps, and diarrhea)
  • Sores in the mouth or on the lips*
  • Constipation
  • Skin rash
  • Abnormal blood tests which suggest that the drug is affecting the liver (Your doctor will discuss the importance of this finding, if any.)

According to the American Cancer Society, the following symptoms are rare

  • Llowered blood platelet count with increased risk of bleeding
  • Major blood clots in the veins of the legs or lungs which can travel to other parts of the body. Tell your doctor immediately if you notice chest pain, shortness of breath, swelling, pain, redness or warmth in an arm or leg.
  • Lowered red blood cell count (anemia)
  • Shortness of breath
  • Cough
  • Feeling sleepy
  • Allergic reaction with shortness of breath, itching, hives, swelling in the mouth or throat, or dizziness, which can happen with the first dose or later doses of this drug
  • Death due to infection, bleeding, severe diarrhea, lung disease, or other problems

There are some other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop the above or any other problems.


Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.