Topotecan

Topotecan inhibits topoisomerase I, an enzyme involved in DNA replication.

Indications

Metastatic carcinoma of the ovary after failure of initial or subsequent chemotherapy. Small cell lung cancer disease after failure of first line chemotherapy.

Dosage

Before administration of topotecan, patient should have a baseline neutrophil count of > 1500 cells/mm3 and a platelet count of >100000 cell/mm3. The recommended starting dose is 1.5mg/m2 by IV infusion over 30 minutes daily for 5 consecutive days, starting on day 1 of a 21 day course. In absence of tumour progression a minimum of four courses are recommended, as tumour response may be delayed.

Contra-Indications

Known hypersensitivity to topotecan, patients with sever bone marrow depression.

Side Effects

Abdominal discomfort, intestinal obstruction,vomiting, diarrhoea, nausea, stomatitis, anorexia. Bone marrow suppression (primarily neutropenia, thrombo-cytopenia, anaemia.

Drug Interactions

Other antineoplastic agents : Myelosuppression may be more severe if topotecan is given with cisplatin. G-CSF : Coadministration of G-CSF and topotecan may prolong duration of neutropenia. If G-CSF has to be used, it should be started only on day 6 of the course i.e., 24 hr. after completion treatment with topotecan.