Etoposide is a semi-synthetic podophyllotoxin derivative and a topoisomerase II inhibitor used as an antineoplastic agent. It is a key component in various combination chemotherapy regimens for treating several malignancies, particularly testicular cancer and small cell lung cancer. In the Indian context, it is widely available as an injectable formulation and an oral capsule, with the 50mg capsule being a common oral dosage form for outpatient and maintenance therapy.
Adult: IV: 50-100 mg/m²/day on days 1-5 of a 21 or 28-day cycle. Oral: Dosage is typically twice the IV dose due to ~50% bioavailability (e.g., 100-200 mg/m²/day for 5 days). Specific dose depends on regimen, indication, and patient status.
Note: Oral: Administer on an empty stomach (1 hour before or 2 hours after meals) with a full glass of water. Capsules must be swallowed whole, not opened or chewed. IV: Must be diluted and infused slowly over 30-60 minutes to avoid hypotension. Faster infusion increases risk of hypersensitivity. Avoid contact with skin/mucous membranes.
Etoposide acts primarily in the late S and G2 phases of the cell cycle. It forms a ternary complex with DNA and the enzyme topoisomerase II, stabilizing the transient 'cleavable complex' that the enzyme creates to manage DNA tangles and supercoils. This stabilization prevents the religation of the DNA strands after the enzyme has created double-strand breaks, leading to the accumulation of permanent DNA breaks.
Pregnancy: FDA Pregnancy Category D. Can cause fetal harm. Teratogenic and embryotoxic in animals. Avoid in pregnancy. Women of childbearing potential must use effective contraception during and for at least 6 months after therapy.
Driving: May cause fatigue, dizziness, or malaise. Patients should be cautioned about driving or operating machinery if affected.
| Warfarin | Etoposide may enhance the anticoagulant effect; increased risk of bleeding. Monitor INR closely. | Major |
| Cyclosporine | Increased etoposide levels and toxicity due to reduced biliary clearance and P-glycoprotein inhibition. | Major |
| Phenytoin, Carbamazepine, Phenobarbital | Reduced etoposide levels and efficacy due to CYP3A4 induction. | Major |
| Ketoconazole, Itraconazole, Voriconazole | Increased etoposide levels and toxicity due to CYP3A4 inhibition. | Major |
| Live Vaccines (e.g., MMR, Varicella) | Risk of disseminated infection due to immunosuppression. Contraindicated. | Major |
Same composition (Etoposide (50mg)), different brands: