Hematopoietic Growth Factors in Idiosyncratic Drug-Induced Neutropenia: Mechanisms, Clinical Evidence, and Future Perspectives

Idiosyncratic, non-chemotherapy drug-induced neutropenia and agranulocytosis are rare but potentially life-threatening adverse drug reactions, frequently affecting older or medically complex patients. Prompt recognition, immediate discontinuation of the causative agent, and supportive care are essential to minimize morbidity and mortality. Hematopoietic growth factors (HGF), particularly granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF), have emerged as valuable therapeutic tools, accelerating neutrophil recovery, reducing infectious complications, and improving clinical outcomes. This review synthesizes current understanding of the pathophysiology, high-risk medications, and clinical presentation of idiosyncratic neutropenia, with an emphasis on HGF pharmacology, formulations, efficacy, and safety. Limitations of the existing evidence, including the lack of prospective trials and heterogeneity in drug exposure and patient populations, are discussed. Finally, we outline future directions, including pharmacogenomic risk stratification, next-generation growth factors, and digital health strategies, highlighting opportunities to optimize individualized patient care. Integrating mechanistic insights with emerging therapeutic approaches positions HGFs as a cornerstone of management and a focus for future research in this rare but serious condition.