Which type of chemotherapy agent includes 5-fluorouracil?

5-fluorouracil is classified as an antimetabolite chemotherapy agent. Antimetabolites are designed to mimic the normal substances within the cell, disrupting the synthesis of nucleic acids, which is essential for cell division and growth. Specifically, 5-fluorouracil interferes with the synthesis of DNA and RNA by inhibiting thymidylate synthase, an enzyme crucial for synthesizing thymidine, which is a building block of DNA. This interference ultimately leads to the inhibition of cancer cell proliferation, making antimetabolites particularly useful in treating various types of cancer.

Understanding this category is vital in oncology, as antimetabolites target rapidly dividing cells, making them effective against tumors that exhibit high growth rates. This mechanism is what distinguishes 5-fluorouracil from other types of chemotherapy agents, such as topoisomerase inhibitors, alkylating agents, and taxanes, which have different modes of action in disrupting cell division or DNA replication.