Which of the following antimetabolites is known to cause cutaneous reactions?

5-Fluorouracil (5-FU) is recognized for its potential to cause cutaneous reactions among the antimetabolites. It is a pyrimidine analog that interferes with DNA synthesis by inhibiting thymidylate synthase, ultimately affecting rapidly dividing cells, including both cancerous cells and healthy tissues such as skin.

The cutaneous reactions associated with 5-FU can manifest as hand-foot syndrome, which is characterized by redness, swelling, and pain in the palms of the hands and soles of the feet. This adverse effect can significantly impact a patient's quality of life and may require dose adjustments or supportive care.

Understanding the skin-related side effects of chemotherapy is vital for patient management. While other treatments may lead to varying degrees of toxicity, their primary side effects do not typically include significant cutaneous reactions in the same way that 5-FU does, making it a crucial point of knowledge for healthcare providers administering these therapies.