Name a common side effect of antimetabolites.

Nausea and vomiting are common side effects associated with antimetabolites due to their mechanism of action in disrupting the normal function of rapidly dividing cells, not only in cancer but also in the gastrointestinal tract. Antimetabolites mimic naturally occurring substances necessary for cell growth and division, which can lead to cellular damage and trigger the body's response, resulting in gastrointestinal toxicity. This toxicity is particularly pronounced because the cells lining the gut are among the most rapidly dividing in the body, making them susceptible to the effects of these drugs.

On the other hand, while hair loss, anemia, and skin rashes can occur as side effects, they are not as universally recognized or prevalent specifically with antimetabolites compared to nausea and vomiting. Hair loss is more typically associated with drugs that directly target rapidly dividing cells in hair follicles. Anemia may arise from a variety of antineoplastic treatments that impact blood cell production, but it is not exclusive to antimetabolite therapy. Skin rashes can be a side effect of some medications but are not a defining characteristic of antimetabolite drugs. Thus, nausea and vomiting stands out as the most characteristic side effect for this category of chemotherapy agents.