Drug information of Topotecan

Topotecan

Drug group:

Topotecan is a cancer medicine that interferes with the growth and spread of cancer cells in the body. Topotecan is used to treat ovarian cancer, small cell lung cancer, and certain types of cervical cancer.

Mechanism of effect

Topoisomerase I relieves torsional strain in DNA by inducing reversible single-strand breaks. Topotecan binds to the topoisomerase I-DNA complex and prevents re-ligation of these single strand breaks. The cytotoxicity of topotecan is thought to be due to double-strand DNA damage produced during DNA synthesis, when replication enzymes interact with the ternary complex formed by topotecan, topoisomerase I, and DNA. Mammalian cells cannot efficiently repair these double-strand breaks.

Pharmacodynamic

Topotecan, a semi-synthetic derivative of camptothecin (a plant alkaloid obtained from the Camptotheca acuminata tree), is an anti-tumor drug with topoisomerase I-inhibitory activity similar to irinotecan.

Pharmacokinetics

Topotecan is rapidly absorbed with peak plasma concentrations occurring between 1 to 2 hours following oral administration. The oral bioavailability of topotecan is approximately 40%. Binding of topotecan to plasma proteins is approximately 35%.Topotecan undergoes a reversible pH-dependent hydrolysis of its lactone moiety; In the urine, 20% of the orally administered dose was excreted as total topotecan and 2% was excreted as N-desmethyl topotecanFecal elimination of total topotecan accounted for 33%

Dosage

Usual Adult Dose for Ovarian Cancer
1.5 mg/m(2) IV over 30 minutes once a day for 5 consecutive days, starting on day 1 of a 21 day course
Usual Adult Dose for Cervical Cancer
0.75 mg/m(2) IV over 30 minutes on days 1, 2, and 3 of each 21 day cycle
Usual Adult Dose for Small Cell Lung Cancer
IV formulation: 1.5 mg/m(2) IV over 30 minutes once a day for 5 consecutive days, starting on day 1 of a 21 day course Oral capsules: 2.3 mg/m(2) orally once a day for 5 consecutive days, starting on day 1 of a 21 day course (round dose to nearest 0.25 mg)
Duration of therapy: Until disease progression

Alerts

1-Bone marrow suppression (primarily neutropenia) is a dose-limiting toxicity of TOPOTECAN.
2-Diarrhea, including severe and life-threatening diarrhea requiring hospitalization, can occur during treatment with TopotecanCapsules.
3-Interstitial lung disease (ILD), including fatalities, has occurred with TOPOTECAN.

Points of recommendation

1-Advise patients on pregnancy planning and prevention
2-TopotecanCapsules can be given without regard to food.
3-Monitor peripheral blood counts frequently during treatment.

Pregnancy level

D

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