Pyrimidine analogues are nucleoside analog antimetabolites which mimic the structure of metabolic pyrimidines.PyrimidineFluorouracilFloxuridineGemcitabine Pyrimidine analogues are nucleoside analog antimetabolites which mimic the structure of metabolic pyrimidines. Pyrimidine antimetabolites are commonly used to treat cancer by interfering with DNA replication.