Beyond the guidelines: Preventing heatwave-related admissions and decompensations through thermopharmacological frailty.

Heatwaves are becoming more frequent, intense, and prolonged in Europe, creating a predictable clinical stressor for multimorbid patients and increasing pressure on Internal Medicine services. Current disease-specific guidelines provide limited practical guidance on how to prevent heat-related admissions and decompensations in patients exposed to polypharmacy, frailty, chronic kidney disease, heart failure, diabetes, cognitive impairment, or social vulnerability. This Editorial proposes the concept of thermopharmacological frailty, a dynamic state in which environmental heat modifies the risk-benefit balance of chronic medication by impairing thermoregulation, hydration, renal perfusion, cardiovascular compensation, cognition, and metabolic stability. We argue that heatwaves should be approached as drug-environment interaction periods, not merely as meteorological events. To move beyond generic heat advice, we outline a pragmatic Internal Medicine pathway based on anticipatory identification of vulnerable patients, mechanism-based medication review, early recognition of warning signals, selective monitoring, and explicit restart criteria after temporary treatment adjustments. Preventing heat-related acute kidney injury, hypotension, falls, delirium, dysglycaemia, heart failure decompensation, and medication toxicity will require exposure-aware medication safety protocols embedded in ambulatory, inpatient, and transitional Internal Medicine care.