Chemotherapy: Topoisomerase Inhibitors (irinotecan, etoposide)

Topoisomerase inhibitors are chemotherapy drugs used to kill lung cancer (malignant) cells. Topoisomerase inhibitors block the enzymes that break and reconnect DNA strands (topoisomerases) that are needed for cell division and growth. ¹ Topoisomerase inhibitors used for lung cancer treatment include irinotecan (Camptosar^®, Camptothecin-11, CPT-11) and etoposide (VePesid^®, Toposar^®).

Irinotecan (Camptosar, Camptothecin-11, CPT-11)

Irinotecan is a chemotherapy drug classified as a topoisomerase I inhibitor and as a plant alkaloid (made from plants). Irinotecan is derived from the Asian “Happy Tree.” Irinotecan is used as a treatment for colon and rectal cancer, and it may also be used in combination with other medications to treat certain forms of lung cancer. Irinotecan is given to the patient through an IV (intravenous) line. Irinotecan is a chemical that can cause irritation and inflammation of the vein in which it is administered, and patients experiencing any pain, redness, or swelling at the injection site should alert a health care professional immediately. The dosage and schedule of irinotecan is determined by several factors, such as the patient’s height and weight, general health, and type of cancer.^2,3

Irinotecan may cause side effects. Common side effects (experienced by greater than approximately 30 percent of patients receiving irinotecan) include diarrhea, nausea, vomiting, weakness, low white blood cells (increasing the risk of infection), low red blood cells (anemia), hair loss, poor appetite, fever, and weight loss. Less common side effects occurring in approximately 10-29 percent of patients include constipation, shortness of breath, difficulty sleeping (insomnia), cough, headache, dehydration, chills, skin rash, flatulence (gas), flushing of the face during infusion, mouth sores, heartburn, and swelling of feet and ankles.² Side effects from irinotecan may be reversible after treatment is finished. This is not a complete list of side effects. Tell your healthcare provider about all conditions, medications, and health history before beginning treatment with irinotecan.

Etoposide (VePesid, Toposar)

Etoposide is a chemotherapy drug classified as a topoisomerase II inhibitor and as a plant alkaloid. Etoposide is derived from the May apple plant and is used to treat many cancers, such as lung, testicular, bladder, prostate, stomach, and uterine cancers, as well as Hodgkin and non-Hodgkin lymphoma, mycosis fungoides, Kaposi's sarcoma, Wilm's tumor, rhabdomyosarcoma, Ewing's sarcoma, neuroblastoma, and brain tumors. Etoposide comes in a capsule, which is taken by mouth, and as an infusion, which is given intravenously (IV). Etoposide is a chemical that can cause irritation and inflammation of the vein in which it is administered, and patients experiencing any pain, redness, or swelling at the injection site should alert a health care professional immediately. The dosage and schedule of etoposide is determined by several factors, such as the patient’s height and weight, general health, and type of cancer.²

Etoposide may cause side effects. Common side effects (experienced by greater than approximately 30 percent of patients receiving etoposide) include low white blood cells (increasing the risk of infection), low platelets (increasing the risk of bleeding), hair loss, chemotherapy-induced menopause, loss of fertility, nausea, vomiting, and low blood pressure during or after infusion. Less common side effects occurring in approximately 10-29 percent of patients include mouth sores, diarrhea, poor appetite, and radiation recall (a severe skin reaction that can occur when chemotherapy is administered at the same time or soon after radiation therapy).^2,4 Side effects from etoposide may be reversible after treatment is finished. This is not a complete list of side effects. Tell your healthcare provider about all conditions, medications, and health history before beginning treatment with etoposide.

Managing side effects

There are many options available to help manage side effects from chemotherapy, and patients should talk to their health care professional about all side effects they experience. Hydration (fluid intake) is very important while receiving chemotherapy, and patients are generally encouraged to drink an adequate amount of fluids every day, which may vary patient to patient (patients should check with their doctor if they have a fluid restriction). To lower the risk of infection, patients receiving chemotherapy may be advised to avoid crowds, people with colds, and wash their hands often.²