Dangerous Medications in Heatwaves: Which Drugs Increase Health Risks During Extreme Heat?

Certain medications increase the risk of dehydration and heatstroke during heatwaves by suppressing thirst or inhibiting the body’s ability to sweat. According to reports from La Libre.be and Marie Claire, GLP-1 agonists like Wegovy and Ozempic, along with psychiatric medications, are particularly concerning during periods of extreme heat.

The pharmaceutical sector issued these warnings on June 19, 2026, as temperatures rose. These drugs can interfere with the body’s natural thermoregulation, making patients more susceptible to heat-related illnesses.

Why do Wegovy and Ozempic increase dehydration risks?

GLP-1 receptor agonists, including Wegovy and Ozempic, can mask the body’s signals for hydration. Marie Claire reports that these medications, primarily used for weight loss and type 2 diabetes, reduce appetite and can also suppress the sensation of thirst.

Patients may not realize they are dehydrated because the biological trigger to drink water is muted. This creates a dangerous gap between the body’s actual fluid needs and the patient’s perceived thirst during a heatwave.

How do psychiatric medications affect heat tolerance?

Patients in psychiatric care are more vulnerable to heat-related complications due to the specific pharmacological properties of their treatments. Le Progrès reports that certain psychiatric drugs impair the body’s ability to regulate internal temperature.

Many antipsychotics and antidepressants have anticholinergic effects. These effects can reduce the production of sweat, which is the primary mechanism the human body uses to cool itself via evaporation.

When sweating is inhibited, the core body temperature rises more quickly. This increases the likelihood of hyperthermia, a condition where the body overheats to dangerous levels.

Which other medications are high-risk during heatwaves?

Beyond GLP-1s and psychiatric drugs, other medication classes pose significant risks during high temperatures. RTL Info notes that several common prescriptions can lead to severe side effects when combined with extreme heat.

• Diuretics: These “water pills” increase the excretion of water and salt from the body, accelerating fluid loss.
• Beta-blockers: These heart medications can limit the heart’s ability to increase its rate, which is necessary to pump blood to the skin’s surface for cooling.
• Tricyclic antidepressants: These often interfere with the sweat response, similar to other anticholinergic agents.

The risk profiles differ by mechanism. While diuretics cause a chemical loss of fluid, beta-blockers create a mechanical failure in the cooling process.

What is the difference between behavioral and physiological risks?

Medical warnings highlight a distinction between how different drugs cause heat vulnerability. GLP-1 agonists like Ozempic create a behavioral risk. The drug changes the patient’s behavior by removing the urge to drink, though the body’s physical ability to sweat remains intact.

In contrast, psychiatric medications and certain antidepressants create a physiological risk. They do not necessarily change the patient’s desire to cool down but instead disable the biological tools, such as sweat glands, required to do so.

This distinction means that simply telling a patient to “drink more water” may be sufficient for some, while others may require active external cooling, such as air conditioning or cool baths, because their bodies cannot cool themselves naturally.

What precautions should patients take?

Pharmaceutical guidelines emphasize that patients should not stop taking prescribed medications without professional oversight. Instead, they are advised to implement strict hydration schedules.

For those on thirst-suppressing medications, drinking water on a timer—rather than waiting for the feeling of thirst—is a primary recommendation. Patients are encouraged to monitor for early signs of heat exhaustion, such as dizziness, confusion, or extreme fatigue.

Medical providers are urged to review the medication lists of vulnerable populations, particularly the elderly and those in psychiatric facilities, before the peak of summer heatwaves.