Topotecan is a chemotherapy medication primarily used to treat certain types of cancer, including ovarian cancer and small cell lung cancer. It works by inhibiting the action of an enzyme called topoisomerase I, which is essential for DNA replication. By disrupting this process, Topotecan helps to prevent cancer cells from dividing and growing. This medication is usually administered intravenously or orally, depending on the specific treatment plan. Common side effects may include nausea, vomiting, and low blood cell counts, which can increase the risk of infection or bleeding. Regular monitoring by healthcare professionals is essential during treatment.