Information about Topotecan
Etoposide and teniposide are semisynthetic analogues of podophyllotoxin that are used as antineoplastic agents in the therapy of several forms of solid tumors, leukemia and lymphoma, usually in combination with other agents.
Liver safety of Topotecan
Both etoposide and teniposide are associated with an appreciable rate of serum enzyme elevations during therapy, and high doses have been implicated in causing clinically apparent acute liver injury including sinusoidal obstruction syndrome.
Mechanism of action of Topotecan
Etoposide (e toe' poe side) and teniposide (ten" i poe' side) are semisynthetic derivatives of podophyllotoxin, an extract from the mandrake plant (American May Apple: Podophyllum peltatum). Both drugs appear to act by binding to and inhibiting topoisomerase II, preventing the healing of DNA breaks that occur during the action of this enzyme in replicating cells. Both agents have antineoplastic activity in vitro and in animal models, and were introduced into clinical practice in the 1980s and 1990s as a part of combination chemotherapy for various leukemias, lymphomas and solid tumors. Etoposide (also known as VP-16) was approved for use in the United States in 1983 and teniposide (VP-26) in 1992. Current formal indications for etoposide include refractory testicular tumors and small cell lung cancer to be used in combination with other agents. Etoposide is available as a solution or lyophilized powder for injection in vials of varying concentrations, and as capsules of 50 mg for oral administration in generic forms and under the commercial name Toposar.
Dosage and administration for Topotecan
The typical dose of etoposide varies by indication and is adjusted for body weight and renal function. The current single approved indication for teniposide is refractory childhood acute lymphoblastic leukemia in combination with other anticancer agents. Teniposide is available in solution in 50 mg vials generically and under the trade name Vumon. The typical dose varies by body weight.
Side effects of Topotecan
Side effects of etoposide and teniposide are similar and include bone marrow suppression, nausea, vomiting, abdominal pain, stomatitis, diarrhea, fatigue, hypotension, allergic reactions, hair loss and peripheral neuropathy. Uncommon, but potentially severe adverse reactions include severe myelosuppression, neutropenic fever or sepsis and anaphylactic reactions. Both agents should be administered only by physicians with experience in the use of chemotherapeutic agents and management of their toxicities.