Camptosar® (irinotecan) is also known as CPT11. It is now available as a generic drug.
When Irinotecan (Camptosar is used)
Irinotecan is approved for treatment of Stage IV or recurrent (metastastic) colorectal cancer. It may be used:
- In the FOLFIRI combination with continuous infusion 5-FU and leucovorin and Avastin® as the first treatment received for metastatic colorectal cancer.
- FOLFIRI if cancer recurs or worsens after earlier FOLFOX or 5-FU treatment.
- Alone, as monotherapy, if cancer progresses on earlier therapy.
- In combination with Erbitux® after progression on earlier therapy, including FOLFIRI or irinotecan monotherapy. Erbitux appears to overcome resistance to irinotecan and give it additional effectiveness.
When Irinotecan is NOT recommended
Camptosar is not recommended for stage III colon cancer. Randomized clinical trials have found no benefit to adding irinotecan to 5FU and leucovorin for stage III colon cancer. In addition there were significantly more toxic side effects, including some treatment deaths in one study.
The IFL regimen is no longer recommended. IFL uses a bolus 5-FU injection rather than continous infusion of 5-FU and side effects are more severe than with FOLFIRI.
Precautions before starting Camptosar
- About 10 percent of the population has a difference in a particular gene (UGT1A1)that makes it difficult for the liver to completely metabolize irinotecan. These people may have an increased risk of serious side effects, particularly low white cells counts and diarrhea.
- The FDA approved label for Camptosar recommends that patients who have this genetic difference begin treatment at a lower dose.
- There is a test for the UGT1A1 gene that can be done before beginning irinotecan treatment. Talk to your doctor about it before you start getting irinotecan.
Irinotecan may cause severe early or late diarrhea — both of which can be life-threatening. Before starting this drug, talk with your doctor so that you have a clear plan to treat diarrhea if it begins. Your plan may involve using Imodium® (loperamide) to manage diarrhea. Loperamide is available over-the-counter and in generic forms.
For chemotherapy-induced diarrhea, the initial dose and how often to take loperamide are different from the instructions on the box. Be sure to talk to your nurse or doctor about the right way to take it.
Early diarrhea happens during or shortly after the irinotecan infusion, with stomach cramping plus other symptoms like runny nose, increased saliva, tears, or flushed skin. It may be prevented or eased by atropine. Tell your oncology nurse if you begin to have these symptoms during your treatment.
Late diarrhea happens more than 24 hours — sometimes from 3 to 11 days — after an irinotecan treatment, but it still can be dangerous because it can lead to dehydration, electrolyte imbalances, or serious bowel infection.
Make sure that your treatment plan includes instructions on what to do with the very first episode of loose, poorly formed, or more frequent bowel movements. Frequently, patients are told to take 2 Imodium® (loperamide) pills (4 mg) after the first episode of loose stools and then take 1 pill (2 mg) every four hours until diarrhea goes away. Your doctor may recommend that you repeat the Imodium pill after each loose stool.
Call the doctor or oncology nurse right away if:
- Diarrhea doesn’t get better within 24 hours.
- You have cramping along with diarrhea.
- You have nausea or vomiting as well as diarrhea.
- You have more than six loose stools within 24 hours.
- You are vomiting or can’t keep fluids down.
- Neutropenia: low white blood cell counts put you at higher risk for infection, especially if you also have diarrhea. White blood cell counts usually recover to normal levels without changing the treatment, but you may need monitoring, dose adjustment, or medication.
- Fever and infection: You may be less able to fight off infection as a result of treatment. Call your doctor or nurse if you have a fever of 100.5 degrees, redness or swelling, painful urination, cough, or other signs, you may have an infection.
- Anemia: Too few red blood cells is also common, but rarely severe. If your blood counts fall low enough, your doctor may prescribe medications or blood transfusions.
- Nausea or vomiting: Usually occurring during or shortly after the infusion, these symptoms can be effectively treated with medicine.
- Blood clots: Irinotecan can increase the risk of blood clots. Watch for redness or painful swelling in a leg or arm.
- Hair loss: About half of patients treated with irinotecan have hair loss, which grows back after treatment ends.
How Irinotecan is given
Irinotecan is given as an IV infusion into a vein.