Which agents are considered cell cycle specific?

Cell cycle-specific agents are those that exert their antitumor effects at specific phases of the cell cycle, leading to more targeted action against actively dividing cancer cells. Antimetabolites and plant alkaloids fall into this category because they interfere with the processes of DNA synthesis and mitosis.

Antimetabolites, such as methotrexate and fluorouracil, are designed to mimic the natural substrates involved in DNA and RNA synthesis, thereby inhibiting the cell's ability to replicate genetic material during the S phase of the cell cycle. Plant alkaloids, such as vincristine and paclitaxel, target specific parts of the mitotic process, with vincristine disrupting microtubule formation during metaphase and paclitaxel stabilizing microtubules to prevent their disassembly, impacting cells in the M phase.

Understanding the specific phases of the cell cycle where these agents act is crucial for maximizing their therapeutic efficacy and timing administration in relation to a patient's treatment regimen. Consequently, antimetabolites and plant alkaloids are quintessential examples of cell cycle-specific agents in chemotherapy.