Etoposide

Etoposide is a topoisomerase inhibitor used in cancer treatment. Here are the conditions it is approved to treat, by product:

• Small cell lung cancer (SCLC) — first-line treatment: Etoposide injection, Avopef, Etopophos, VePesid capsules, and Etoposide capsules are all used in combination with other chemotherapy agents. Avopef is also approved for use with immunotherapy.
• Refractory testicular tumors (cancer that has not responded to prior surgery, radiation, and chemotherapy): Etoposide injection, Avopef, Etopophos, and Toposar are approved, always in combination with other drugs. Capsule forms are not approved for this use — the label notes that adequate data are unavailable.

Etoposide targets an enzyme called topoisomerase II, which cancer cells rely on to unwind and repair their DNA during replication. By interfering with this enzyme, etoposide causes breaks in the DNA strands. It can also generate free radicals that further damage DNA. The end result is that cancer cells get stuck in a phase of the cell cycle called G2 — they cannot divide — and they die.

At different concentrations, etoposide has different effects on cells: at higher levels it destroys cells entering active division, and at lower levels it blocks them from even getting there. This dose-dependent behavior is managed carefully by your oncology team.

Etoposide is available as an intravenous (IV) injection given in a clinical setting, or as capsules taken by mouth. Injectable forms are given by slow infusion — never a rapid push into the vein. Capsules are taken orally and must be kept refrigerated at home. Treatment is typically given in cycles over several consecutive days, with a rest period of 3 to 4 weeks between cycles to allow blood counts to recover.

• IV infusions are given in a hospital or infusion center by trained staff
• Capsules should be handled with waterproof gloves and stored in the refrigerator
• Your prescriber sets the exact schedule based on your cancer type, other medications, kidney function, and blood counts
• Dose may be reduced if kidney function is impaired — always tell your team about any health changes

Etoposide commonly causes the following side effects:

• Low white blood cell counts (leukopenia) — increases infection risk
• Low platelet counts (thrombocytopenia) — increases bleeding and bruising risk
• Anemia (low red blood cells) — may cause fatigue
• Nausea and vomiting (usually mild to moderate and manageable with anti-nausea medications)
• Hair loss (alopecia) — often significant but usually reversible
• Loss of appetite
• Diarrhea or mouth sores
• Fatigue and weakness

Serious reactions to watch for include signs of severe infection or bleeding, sudden low blood pressure during infusion, a severe allergic reaction (wheezing, throat tightening, hives), pain or swelling at the IV site, and any new or unusual bruising. Rarely, a secondary leukemia has occurred. Contact your care team immediately if any of these arise.

• Severe bone marrow suppression: Etoposide's most dangerous side effect is a sharp drop in blood cell counts, which can cause life-threatening infections or bleeding. Blood counts must be checked before every cycle. Treatment is stopped or delayed if counts are critically low.
• Serious allergic/infusion reactions: Anaphylactic-like reactions — including difficulty breathing, rapid heartbeat, low blood pressure, and facial swelling — can occur, sometimes fatally. IV infusions must be given slowly, and emergency treatment must be immediately available.
• Tissue damage from IV leakage (extravasation): If etoposide leaks outside the vein during infusion, it can cause swelling, pain, and tissue death at the injection site.
• Secondary leukemia: Rarely, a new blood cancer has developed in patients treated with etoposide.
• Fetal harm: Etoposide can cause serious birth defects and pregnancy loss. Effective contraception is essential during and after treatment.
• Fertility effects: Both men and women may experience temporary or permanent fertility changes. Discuss this with your doctor before starting treatment.
• Alcohol content (Avopef): Avopef injection contains ethanol, which may impair the ability to drive or use machinery right after an infusion.

Tell your doctor and pharmacist about all medications, supplements, and herbal products you take. Key interactions include:

• Strong CYP3A inhibitors (certain antifungals like ketoconazole, some HIV medications): can increase etoposide exposure, raising the risk of toxic side effects — avoid if possible
• Strong CYP3A inducers (such as rifampin, certain anti-seizure drugs): can lower etoposide levels, potentially reducing its effectiveness — avoid if possible
• Warfarin and other vitamin K antagonists (blood thinners): etoposide can elevate INR, increasing bleeding risk — closer monitoring and dose adjustment of the blood thinner may be needed
• Aspirin, sodium salicylate, phenylbutazone: these can displace etoposide from blood proteins, potentially increasing etoposide's effects
• Cisplatin: prior or concurrent use is associated with slower clearance of etoposide from the body
• Alcohol (Avopef specifically): the ethanol in Avopef may affect the central nervous system immediately after infusion

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Do not use etoposide if you have had a severe allergic reaction to it or any of its ingredients
• Tell your doctor if you are pregnant or trying to become pregnant — etoposide can cause serious fetal harm, including birth defects and pregnancy loss
• Do not breastfeed during treatment or for at least 1 week after the last dose
• Use effective contraception: women for at least 6 months, men for at least 4 months after the last dose
• Tell your doctor if you have kidney problems — dose reduction may be needed if kidney function is significantly reduced
• Patients with low blood albumin levels are at higher risk for etoposide side effects and need closer monitoring
• Older adults (65+) have a higher risk of severe blood count drops, mouth sores, dehydration, confusion (somnolence), and infections
• The safety and effectiveness of Avopef have not been established in pediatric (child) patients
• Tell your team about all other medications, including over-the-counter drugs and supplements, before starting etoposide

There is no established antidote for an etoposide overdose. If an overdose is suspected, emergency medical care should be sought immediately. The primary concerns would likely be severe bone marrow suppression and its consequences, including life-threatening infection and bleeding.

Etoposide's main effect in the body is disrupting how cancer cells divide. It causes DNA strand breaks by interacting with the topoisomerase II enzyme and by generating damaging free radicals. At higher drug concentrations, cells entering active division are destroyed outright; at lower concentrations, cells are prevented from progressing into division at all. The result, regardless of concentration, is cell cycle arrest — cancer cells stop multiplying — and ultimately cancer cell death.

When given intravenously, etoposide follows a two-phase pattern: it distributes rapidly through the body in about 1.5 hours, then is cleared over 4 to 11 hours. It is strongly bound to blood proteins (about 97%), so low albumin levels can increase the amount of active, unbound drug in circulation. Etoposide is broken down partly through the liver (via the CYP3A4 enzyme pathway) and partly excreted unchanged through the kidneys and bile; patients with significant kidney impairment may need dose adjustments. When taken as a capsule, only about half the dose is absorbed into the bloodstream compared to IV administration, and absorption can vary quite a bit from person to person.

Store at 20°C to 25° C (68°F to 77° F); excursions permitted to 15°C to 30°C (59°F to 86°F). store the partially used multiple-dose vial in the original carton at controlled room temperature, 20°C to 25°C (68°F to 77°F) for up to 28 days .