antifungal pyrimidine analog Pyrimidine analogs are a group of antifungals that are nucleosides, that mimic the structure of natural pyrimidines. Some pyrimidine analogs have the potential to convert into 5-fluorouracyl and further to 5-fluorodeoxyuridine inside the fungal cell. Subsequently, 5-fluorodeoxyuridine interferes with DNA, RNA, and protein synthesis. The transformation of flucytosine into 5-fluorouracyl is catalyzed by the action of the fungal enzyme cytosine deaminase (encoded by the yeast gene FCY1), which is not present in humans. The only pyrimidine analog with antimycotic properties currently in use for human treatment is flucytosine. https://doi.org/10.3390/genes9090461 Although it is one of the more effective and safest antimycotic in the health system, it is not used in monotherapy due to the rapid development of resistance towards this drug