Irinotecan

Irinotecan is a prescription medication used alone or in combination with other medications to treat colon and rectal cancer (cancer that begins in the large intestine). It is also used to treat advanced pancreatic cancer (Onivyde). Irinotecan belongs to a group of drugs called topoisomerase I inhibitors. These work by stopping the growth of cancer cells.

Irinotecan comes as a liquid to be given over 90 minutes intravenously (into a vein) by a healthcare professional.

Common side effects include nausea, vomiting, and stomach pain, diarrhea.

Irinotecan is a prescription medication used alone or in combination with other medications to treat colon and rectal cancer (cancer that begins in the large intestine) that has spread to other parts of the body. It is also used to treat advanced pancreatic cancer (Onivyde) in combination with fluorouracil and leucovorin. 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Irinotecan may be found in some form under the following brand names:

• Camptosar

• Onivyde

Common side effects include the following:

• nausea
• vomiting
• stomach pain
• diarrhea
• constipation
• loss of appetite
• lowered blood counts
• weakness
• fever
• a decrease in body weight
• hair loss

This is not a complete list of this medication’s side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

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

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• atazanavir (Reyataz)
• medications for seizures such as carbamazepine (Carbatrol, Epitol, Tegretol), phenobarbital (Luminal), phenytoin (Dilantin, Phenytek)
• rifabutin (Mycobutin)
• rifampin (Rifadin, Rimactane, in Rifamate and Rifater)
• St. John's wort
• ketoconazole (Nizoral)
• other chemotherapy medications for cancer
• diuretics ('water pills')
• laxatives such as bisacodyl (Dulcolax) or senna (in Correctol, Ex-Lax, Peri-Colace, Senokot)

This is not a complete list of all drug interactions. Ask your doctor or pharmacist for more information.

Serious side effects have occurred with use of irinotecan.

• You may experience the following symptoms while you are receiving a dose of irinotecan or for up to 24 hours afterward: runny nose, increased saliva, shrinking pupils (black circles in the middle of the eyes), watery eyes, sweating, flushing, diarrhea (sometimes called 'early diarrhea'), and stomach cramps. Tell your doctor if you experience any of these symptoms. Your doctor can give you medication to prevent or treat these symptoms.
• You may also experience severe diarrhea (sometimes called ''late diarrhea'') more than 24 hours after you receive irinotecan. This type of diarrhea can be life threatening since it can last a long time and lead to dehydration, infection, kidney failure, and other problems. Tell your doctor if you have or have ever had a bowel obstruction (blockage in your intestine). Tell your doctor and pharmacist if you are taking any of the following medications: other chemotherapy medications for cancer; diuretics ('water pills'); or laxatives such as bisacodyl (Dulcolax) or senna (in Correctol, Ex-Lax, Peri-Colace, Senokot).
• Before you begin your treatment with irinotecan, talk to your doctor about what to do if you have late diarrhea. Your doctor will probably tell you to keep loperamide (Imodium AD) on hand so that you can begin to take it right away if you develop late diarrhea. Your doctor will probably tell you to take loperamide at regular intervals throughout the day and night. Be sure to follow your doctor's directions for taking loperamide; these will be different than the directions printed on the package label of loperamide. Your doctor will also tell you which foods you should eat and which foods you should avoid in order to control diarrhea during your treatment. Drink plenty of fluids and follow this diet carefully.
• Call your doctor right away the first time you have diarrhea during your treatment. Also call your doctor immediately if you experience any of the following symptoms: fever (temperature higher than 100.4°F); shaking chills; black or bloody stools; diarrhea that does not stop within 24 hours; lightheadedness, dizziness, or fainting; or severe nausea and vomiting that stops you from drinking anything. Your doctor will watch you carefully and may treat you with fluids or antibiotics if needed.
• Irinotecan may cause a decrease in the number of blood cells made by your bone marrow. Tell your doctor if you have or have ever had a blood disease or Gilbert's syndrome (decreased ability to break down bilirubin, a natural substance in the body) and if you are being treated with radiation to your stomach or pelvis (area between the hip bones) or if you have ever been treated with this type of radiation. If you experience any of the following symptoms, call your doctor immediately: fever, chills, cough, or other signs of infection; shortness of breath; fast heartbeat; headache; dizziness; pale skin; confusion; extreme tiredness, or unusual bleeding or bruising.

Do not take irinotecan if you are allergic to it or to any of the inactive ingredients.

Your doctor will tell you about a special diet to follow to help control diarrhea during your treatment. Follow these instructions carefully

Grapefruit and grapefruit juice may interact with this medication and can lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

Before receiving irinotecan,

• tell your doctor and pharmacist if you are allergic to irinotecan, sorbitol, or any other medications.
• tell your doctor if you are taking ketoconazole (Nizoral). Your doctor will probably tell you not to take ketoconazole for one week before you begin your treatment with irinotecan or during your treatment.
• tell your doctor if you are taking St. John's wort. You should not take St. John's wort for 2 weeks before you begin your treatment with irinotecan or during your treatment.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take.
• tell your doctor if you have or have ever had diabetes; fructose intolerance (inability to digest the natural sugar found in fruit); or liver, lung, or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. You should not become pregnant while you are receiving irinotecan. Talk to your doctor about birth control methods that will work for you. If you become pregnant while receiving irinotecan, call your doctor. Irinotecan may harm the fetus (unborn baby).
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are receiving irinotecan.
• you should know that irinotecan may make you dizzy or affect your vision, especially during the first 24 hours after you receive a dose. Do not drive a car or operate machinery until you know how this medication affects you.
• talk to your doctor before you receive any vaccinations during your treatment with irinotecan.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category D. You should not become pregnant while you are receiving irinotecan. Talk to your doctor about birth control methods that will work for you. If you become pregnant while receiving irinotecan, call your doctor. Irinotecan may harm the fetus (unborn baby).

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if this medication crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using this medication.

Irinotecan comes as a liquid to be given over 90 minutes intravenously (into a vein) by a doctor or nurse. It is usually given not more often than once a week, according to a schedule that alternates one or more weeks when you receive irinotecan with one or more weeks when you do not receive the medication. Your doctor will choose the schedule that will work best for you.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.
 The dose your doctor recommends may be based on the following:

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your weight
• your height
• your age
• your gender

Colorectal cancer combination regimen 1: Irinotecan 125 mg/m² injection over 90 minutes on days 1, 8,15, 22.

Colorectal cancer combination regimen 2: Irinotecan 180 mg/m² injection over 90 minutes on days 1, 15, 29.

Colorectal cancer single agent regimen 1: Irinotecan 125 mg/m² injection over 90 minutes on days 1, 8, 15, 22 followed by a 2-week rest.

Colorectal cancer single agent regimen 2: Irinotecan 350 mg/m² injection over 90 minutes on day 1 every 3 weeks.

Advanced Pancreatic Cancer: Irinotecan 70 mg/m² injection over 90 minutes every 2 weeks. 

Advanced Pancreatic Cancer for patients with the UGT1A1*28 allele: Irinotecan 50 mg/m² to 70 mg/m² injection over 90 minutes every 2 weeks. 

Since this medication is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if an overdose is suspected, seek emergency medical attention.
 

Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests to check your body's response to irinotecan.