Tepadina, known generically as thiotepa, is a potent alkylating agent used in the treatment of various types of cancer, including breast cancer, ovarian cancer, bladder cancer, and certain types of lymphomas. It works by interfering with the DNA replication process in cancer cells, thereby inhibiting their growth and proliferation. Tepadina is often used in preparation for bone marrow or stem cell transplantation, as it can help to suppress the immune system and reduce the risk of transplant rejection. Administered intravenously, its use requires careful monitoring by healthcare professionals due to its potential for causing severe side effects, including myelosuppression, which is a decrease in bone marrow activity leading to reduced blood cell production. Despite its risks, Tepadina remains a critical component of certain chemotherapy regimens, offering hope for remission and extended survival in patients facing difficult-to-treat cancers.