5azacytydyna

5-azacytydyna, or 5-azacytidine, is a nucleoside analogue used in the treatment of myelodysplastic syndromes and certain leukemias. It is a cytidine analogue in which the carbon at position 5 is replaced by nitrogen.

Mechanism: It inhibits DNA methyltransferases, leading to hypomethylation and re-expression of silenced genes. Incorporation into RNA and DNA contributes to its cytotoxic and gene-regulatory effects.

Clinical use: Indicated for patients with myelodysplastic syndromes; sometimes used in combination regimens for AML in older adults or unsuitable for intensive chemotherapy. It may modify disease course as a disease-modifying agent rather than a cytotoxic drug alone.

Pharmacology and administration: Typically given by subcutaneous injection or intravenous infusion; common regimens include 75 mg/m2 daily for seven days in a 28-day cycle. Dosing varies by indication and setting.

Safety: Side effects include myelosuppression, especially neutropenia and thrombocytopenia, fatigue, nausea, vomiting, mucositis, diarrhea. Risk of infection; use with caution in pregnancy.

History and status: First approved in the early 2000s; marketed as Vidaza; used widely in myelodysplastic syndromes and other myeloid neoplasms.