Chemotherapy Biotherapy Certification ONS Practice Testq

Which of the following best describes antimetabolites?

1. Drugs that kill cells during any phase

2. Agents that interfere with DNA synthesis

3. Only given to patients with solid tumors

4. Used only in conjunction with radiation therapy

The correct answer is: Agents that interfere with DNA synthesis

Antimetabolites are a class of chemotherapy drugs that work by mimicking the natural substances that are necessary for the growth and reproduction of cells, particularly cancer cells. They interfere with DNA synthesis and function, which hinders the ability of the cancer cells to proliferate. In more detail, these agents disrupt metabolic processes involved in the synthesis of nucleotides, the building blocks of DNA. For example, some antimetabolites mimic purines or pyrimidines, thereby inhibiting enzymes crucial for DNA repair and replication processes. This action leads to cell cycle arrest and can result in cell death, particularly in rapidly dividing cells typical of many cancers. The other options do not accurately represent the unique mechanism of action or appropriate usage of antimetabolites. For instance, stating that they kill cells during any phase is misleading, as they are most effective in the S phase of the cell cycle when DNA synthesis is taking place. Suggesting that they are only given to patients with solid tumors ignores their use in hematologic malignancies, where they can also be effective. Lastly, indicating that they are used only in conjunction with radiation therapy overlooks their ability to be used as standalone therapies or in combination with other types of chemotherapy, depending on the treatment plan