<p>The increasing frequency, duration and intensity of heat waves pose substantial health risks, particularly for vulnerable populations, including people with diabetes. Drug therapy is assumed to be an important factor influencing the occurrence of heat-related illness. In fact, numerous active ingredients can impair the body’s ability to respond to heat stress (thermoregulation), for example, by disrupting efficient heat-dissipating mechanisms such as perspiration and peripheral vasodilation. Some drugs increase the risk of volume depletion, lead to electrolyte disturbances, reduce vigilance or decrease thirst sensation. As the clinical relevance of the influence of drugs on thermoregulatory processes cannot be clearly determined at present, it is up to the physician to derive patient-specific recommendations for adapting drug treatment in phases of prolonged heat. It should also be taken into account that extreme ambient temperatures affect pharmacokinetic parameters, resulting in altered plasma levels of some active ingredients. Regarding the absorption of drugs that are administered cutaneously (insulin, opioids), there is evidence of a&#xa0;heat-driven increase in systemic exposure. The decisive factor here is the heat-induced increase in skin blood flow. As this is at the expense of blood flow to the organs, the pharmacokinetic processes distribution, metabolism and excretion are also affected by heat exposure. Particular challenges arise when dehydration occurs.</p>