Topic overview

Start with the big picture

Antimetabolites interfere with nucleotide production or become incorporated into genetic material, disrupting replication and, in some cases, RNA function. The lesson groups these drugs into folate antagonists, pyrimidine analogs, and purine analogs. It connects each group’s mechanisms to agents such as methotrexate, 5-fluorouracil, cytarabine, and 6-mercaptopurine, alongside selected cancer uses and adverse effects. Examples include marrow and gastrointestinal toxicity, methotrexate-related mucositis and nephrotoxicity, and cytarabine-associated cerebellar toxicity. The material also introduces supportive measures and clinically relevant distinctions, including leucovorin rescue and folate/B12 supplementation with pemetrexed. This preview provides a framework for organizing the drug classes; the full lesson develops the individual agents and resistance mechanisms in greater detail.