|Systematic (IUPAC) name|
4'-demethyl-epipodophyllotoxin 9-[4,6-O-(R)-ethylidene-beta-D-glucopyranoside], 4' -(dihydrogen phosphate)
|Bioavailability||Highly variable, 25 to 75%|
|Metabolism||Hepatic (CYP3A4 involved)|
|Biological half-life||Oral: 6 h., IV: 6-12 h., IV in children: 3 h.|
|Excretion||Renal and fecal|
|ATC code||L01CB01 (WHO)|
|Molar mass||588.557 g/mol[[Script error: No such module "String".]]|
Etoposide phosphate (brand names: Eposin, Etopophos, Vepesid, VP-16) is a cancer drug. It inhibits the enzyme topoisomerase II, which unwinds DNA, and by doing so causes DNA strands to break. Cancer cells are less able to repair this damage than healthy cells. It is used as a form of chemotherapy for cancers such as Ewing's sarcoma, lung cancer, testicular cancer, lymphoma, non-lymphocytic leukemia, and glioblastoma multiforme. It is often given in combination with other drugs. It is also sometimes used in a conditioning regimen prior to a bone marrow or blood stem cell transplant.
The name VP-16 likely comes from a compounding of the last name of the chemists who performed early work on the drug (von Wartburg and von Kuhn) and podophyllotoxin. Another chemist who was integral in the development of podophyllotoxin-based chemotherapeutics was Hartmann F. Stähelin.
Mechanism of Action
Etoposide forms a ternary complex with DNA and the topoisomerase II enzyme, preventing re-ligation of the DNA strands. This causes errors in DNA synthesis and promotes apoptosis of the cancer cell.
It is given intravenously or orally in capsule form. If the drug is given by IV it must be done slowly over a 30 to 60 minute period because it can lower blood pressure as it is being administered. Blood pressure is checked often during infusing, with the speed of administration adjusted accordingly.
Patients are advised to drink large amounts of fluids after treatment to prevent damage to the bladder and kidneys, typically 1.5 to 3.5 litres of water on the day of treatment and for several days after.
- low blood pressure
- hair loss
- pain and or burning at the IV site
- constipation or diarrhea
- metallic food taste
- Bone marrow suppression, leading to:
Less common are:
- nausea and vomiting
- allergic type reactions
- fever, often occurring shortly after IV administration and not due to infection
- mouth sores
- Acute myeloid leukemia