Sulfonylureas beyond diabetes: A comprehensive review on anticancer and off-target effects (1956-2025)

Sulfonylureas (SUs) have been used in the treatment of type 2 diabetes since the 1950s, yet growing evidence shows that many members of this class also exert biologically relevant off-target effects that may be exploited in oncology and other therapeutic contexts. This review provides a structured overview of the literature from 1956 to 2025, integrating preclinical studies, clinical and epidemiological data, pharmacovigilance signals, and patent activity. To facilitate comparison across compounds, the available evidence is organized into drug-specific mechanistic maps rather than treated as a uniform class effect. Across the literature, SUs have been linked to modulation of K_ATP channels, ABC transporters involved in multidrug resistance, gap-junction communication, redox balance, mitochondrial function, inflammatory signaling, and DNA damage-related pathways. However, these activities differ markedly between individual agents. Glibenclamide emerges primarily as a chemosensitizing and transporter-modulating compound, gliclazide as a drug with antioxidant, anti-inflammatory, and DNA-protective properties, glimepiride as a promising synergistic agent with additional AKR1C3-inhibitory activity, tolbutamide as a modulator of gap-junction signaling and mitochondrial stability, and chlorpropamide derivatives as ALDH-targeting chemosensitizers. At the same time, the review highlights major translational constraints, including weak baseline cytotoxicity for most SUs, frequent exposure mismatches between experimental and clinical settings, heterogeneous safety profiles, photoreactivity, and limited commercial incentives for development, while also outlining practical strategies to address these limitations. Overall, SUs should not be viewed as a single repurposing candidate, but as a chemically related set of drugs that require indication-specific and compound-specific selection for future oncology applications.