What phase of the cell cycle do antimetabolites primarily target?

Antimetabolites primarily target the S phase of the cell cycle, which is the phase where DNA synthesis and replication occur. These drugs mimic the building blocks of DNA and interfere with the synthesis of nucleic acids, which is crucial during this phase. By inhibiting the enzymes involved in DNA replication, antimetabolites effectively disrupt the process of cell division, leading to cell death or halted proliferation of rapidly dividing cancer cells.

The S phase is critical for cancer treatment because many cancer cells are characterized by their rapid growth and division. By focusing on this phase, antimetabolites can selectively target cancer cells while having a lesser effect on non-dividing cells. This specificity is essential for minimizing damage to normal tissues during chemotherapy. Understanding this mechanism helps in optimizing treatment regimens and managing side effects associated with chemotherapy.