Etoposide
A podophyllotoxin derivative that blocks topoisomerase II, used for small cell lung cancer and refractory testicular cancer.
Drug card
- How it works
- Blocking topoisomerase II from resealing DNA, leaving double-strand breaks
- Used for
- Small cell lung cancer, first-line in combination
- Refractory testicular tumors, in combination
- Known for
- Bone marrow suppression, dose-limiting
- Low blood pressure with rapid infusion
- Secondary acute leukemia
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does etoposide work?
A semisynthetic derivative of podophyllotoxin, from the mandrake root, that binds topoisomerase II and stops it rejoining cut DNA, so strand breaks accumulate, mainly in the S and G2 phases. Unlike the vinca alkaloids and taxanes, it does not interfere with microtubule assembly.
Uses
What is etoposide used for?
- Small cell lung cancer, first-line in combination
- Refractory testicular tumors, in combination
Side effects
Side effects of etoposide
- Bone marrow suppression, dose-limitingKnown forSerious
- Low blood pressure with rapid infusionKnown for
- Secondary acute leukemiaKnown forSerious
- Hair loss, sometimes total
- Nausea and vomiting
- Mucositis and esophagitis
- Anaphylaxis-like reactionsSerious
- Severe skin reactions (such as SJS/TEN)Serious
- Pneumonitis and lung fibrosisSerious
- Optic neuritis and brief blindnessSerious
- SeizuresSerious
- Liver toxicity at high dosesSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Check blood counts before each dose, and withhold it until low platelets or neutrophils recover.
- Infuse over 30 to 60 minutes; rapid injection causes hypotension.
- Reduce the dose in kidney impairment; low serum albumin raises toxicity.
- High-dose ciclosporin raises etoposide levels.
Remember it
A way to remember it
Etoposide jams the DNA scissors open.
Topoisomerase II cuts both DNA strands to untwist them and then rejoins them; etoposide stops the rejoining, so the cut ends stay apart and the cell dies.
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Its class
Topoisomerase II inhibitors
Topoisomerase II relieves the twisting stress in DNA by cutting both strands and then rejoining them. Anticancer inhibitors such as etoposide trap the enzyme on the DNA and stop the rejoining, so double-strand breaks pile up, replication and transcription stall, and the cell dies by apoptosis. Etoposide acts mainly in the S and G2 phases of the cell cycle.
Easily mixed up with anthracyclines and fluoroquinolones.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Cancer chemotherapy
Etoposide is one of 9 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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