Teniposide

Definition

Teniposide is a chemotherapy medicine used to treat cancer by destroying cancerous cells. Teniposide is also known as the brand name Vumon and may also be referred to as VM-26.

Purpose

Teniposide is approved by the Food and Drug Administration (FDA) as induction therapy (an initial, intensive course of chemotherapy) for refractory childhood acute lymphoblastic leukemia. Teniposide is used in combination with other chemotherapy drugs. It has also been used in some adult leukemias and lung cancers.

Description

Teniposide is a clear liquid for infusion into a vein. Teniposide is a semisynthetic derivative of podophyllotoxin found in extracts of the mandrake plant. It is a member of the group of chemotherapy drugs known as topoisomerase II inhibitors. Topoisomerase II is one of the enzymes involved in rearrangement of DNA structures, such as temporarily breaking DNA strands and resealing them. This process is necessary for cell replication, and topoisomerase II inhibitors interfere with this important process as it prevents the cells from further dividing and multiplying and the cells subsequently die.

Recommended dosage

A teniposide dose can be determined using a mathematical calculation that measures a person's body surface area (BSA). This number is dependent upon a patient's height and weight. The larger the person the greater the body surface area. Body surface area is measured in the units known as square meter (m²). The body surface area is calculated and then multiplied by the drug dosage in milligrams per square meter (mg/m²). This calculates the actual dose a patient is to receive.

To treat refractory childhood leukemia

Teniposide is dosed at 165 mg per square meter as an infusion into a vein over 30-60 minutes and is given with the chemotherapy drug cytarabine at a dose of 300 mg per square meter. This combination is given twice a week for eight to nine doses.

Other leukemia dosing includes teniposide 100 mg per square meter once or twice weekly, and teniposide 250 mg per square meter with the chemotherapy drug vincristine 1.5 mg per square meter given into a vein each week for four to eight weeks.

Patients with significant kidney and liver problems may need to receive a smaller dose of teniposide than patients with normal kidney and liver function.

Patiets with Down syndrome should receive a smaller dose with the initial treatment.

Precautions

Blood counts will be monitored regularly while on teniposide therapy. During a certain time period after receiving this drug, there is an increased risk of getting infections. Caution should be taken to avoid unnecessary exposure to germs. Patients with a known previous allergic reaction to chemotherapy drugs should tell their doctor before treatment. Patients who may be pregnant or trying to become pregnant should tell their doctor before receiving teniposide. Chemotherapy can cause men and women to be sterile (unable to have children). Patients should check with their doctors before receiving live virus vaccines while on chemotherapy.

Side effects

The most common side effect of teniposide is low blood counts, referred to as myelosuppression. When the white blood cell count is lower than normal, known as neutropenia, patients are at an increased risk of developing a fever and infections. Teniposide also causes the platelet count to fall. Platelets are blood cells in the body that allow for the formation of clots. When the platelet count is low patients are at an increased risk for bruising and bleeding. If the platelet count remains too low, a platelet blood transfusion is an option. Low red blood cell counts, referred to as anemia, may make patients feel tired, dizzy and lacking energy. A drug known as erythropoietin may be given to increase a patient's red blood cell count.

Teniposide infusions given too quickly into the vein can cause a significant drop in blood pressure. This can usually be avoided by administering the drug over a time period of at least 30-60 minutes. Teniposide can also cause mild to moderate nausea and vomiting. Patients will be given medicines known as antiemetics before receiving teniposide to help prevent or decrease this side effect. Diarrhea, loss of appetite (anorexia), and mouth sores and inflammation are also common. Rarely, allergic or anaphylactic-type reactions that include fever, sweating, tongue swelling, chest tightness, itching, shortness of breath, low blood pressure and increase heart rate, have occurred.

Other less common side effects caused by teniposide include rash, itching, hair loss (alopecia), liver and kidney problems, fatigue, seizures, tingling, fever, development of another type of cancer or leukemia due to taking the drug, and redness and pain at the site of injection into the vein. All side effects a patient experiences should be reported to their doctor.

Interactions

There is an increase risk of worsening some of the side effects of teniposide when it is administered with the medicines sodium salicylate, tolbutamide (a drug to lower blood sugar levels), or sulfamethizole (an antibiotic).

KEY TERMS

Anemia

Red blood cell count that is lower than normal.

Chemotherapy

Specific drugs used to treat cancer

Refractory cancer

Cancer that is not responding to treatment

DNA

Deoxyribonucleic acid, the genetic material inside cells that allows cells to function, separate, into two cells, and make more cells

Food and Drug Administration

A government agency that oversees public safety in relation to drugs and medical devices. The FDA gives the approval to pharmaceutical companies for commercial marketing of their products

Induction therapy

Initial intensive course of chemotherapy designed to wipe out abnormal cells and allow regrowth of normal cells.

Intravenous

Administered into the body through a vein.

Neutropenia

White blood cell count that is lower than normal.