THE MEDICINES AND HEALTHCARE PRODUCTS REGULATORY AGENCY (MHRA) has warned patients in the UK to manage medication carefully during record-breaking summer temperatures, highlighting risks for those on common drugs like SSRIs and diabetes medications, according to EMJ.
SSRIs and the Body’s Cooling Mechanism
Selective Serotonin Reuptake Inhibitors (SSRIs), widely prescribed for depression and anxiety, can disrupt the body’s ability to regulate temperature, according to ABC11 News. These medications, which include Prozac and Zoloft, affect serotonin levels, potentially impairing the hypothalamus—the brain’s internal thermostat. “My patients who are taking SSRIs do tell me that they sweat more. A lot of them do. And it is definitely a side effect that happens,” said Dr. Jacob Wood, a family medicine physician at Baton Rouge General, as reported by WAFB.
While core temperatures remain stable, increased sweating raises dehydration risks. “The studies have shown that when they measure people’s core temperatures who are on SSRIs, they’re maintaining their core temperature fine. They’re just sweating more,” Wood explained. He emphasized pre-hydration, particularly for those engaging in outdoor activity, and advised against abruptly stopping medication without medical guidance.
Heat Sensitivity Across Medication Classes
Heat poses risks beyond SSRIs. ClickOnDetroit identified several drug classes that interfere with thermoregulation. Diuretics, such as Lasix, increase urination and electrolyte loss, while beta blockers like Lopressor limit the heart’s ability to respond to heat stress. ACE inhibitors and ARBs, commonly used for hypertension, can reduce thirst signals, masking dehydration.
Antipsychotics and tricyclic antidepressants also affect sweating, with the latter potentially reducing it. Stimulants for ADHD, like Ritalin, boost metabolic activity, raising overheating risks. Over-the-counter allergy medications, including Benadryl, further complicate matters by reducing sweat production and impairing alertness to heat illness symptoms.
Diabetes Medications: A Unique Set of Risks
The MHRA’s guidance specifically addresses diabetes management during heatwaves. Insulin and metformin, key treatments for the condition, can exacerbate dehydration or obscure early symptoms of heat-related illness. “Some medicines can also make you more likely to burn in the sun, feel dizzy, or get dehydrated, especially if you’re taking diuretics or have a condition like asthma, heart disease, or diabetes,” said Alison Cave, Chief Safety Officer at the MHRA, as cited in EMJ.
Continuous glucose monitors (CGMs) may also malfunction in extreme heat, leading to unreliable readings. The agency urged patients to store devices in cool, dry places and consult pharmacists if issues arise. For those on SGLT2 inhibitors like Jardiance, the risk of dehydration is heightened, requiring closer monitoring of fluid intake.
Practical Steps for Patients
Health experts across sources agree on proactive measures. Dr. Glatter from Hofstra University, cited in ABC11 News, recommended staying indoors during peak heat, wearing loose clothing, and increasing electrolyte intake. “If you feel like the sweating is just getting to you and it’s just too much, do talk to your doctor about it because there may be some other options to cover the same stuff,” advised Dr. Wood, as reported by WAFB.
The CDC’s advice to drink water consistently, even without thirst, aligns with these recommendations. For those on diuretics or managing chronic conditions, the MHRA emphasized creating a “hot day plan” with healthcare providers to adjust medication or hydration strategies.
Why This Matters: A Growing Public Health Concern
With July 2026 experiencing record temperatures, the interplay between heat and medication has become a critical issue. The CDC estimates 13% of U.S. adults take SSRIs, while diabetes affects over 37 million Americans. As climate change intensifies heatwaves, understanding these interactions is essential for preventing heat-related illnesses.
“The studies have shown that when they measure people’s core temperatures who are on SSRIs, they’re maintaining their core temperature fine. They’re just sweating more,” said Dr. Wood, highlighting the need for tailored advice. For patients on multiple medications, the risks compound, underscoring the importance of individualized care.
As heatwaves become more frequent, healthcare providers and patients must remain vigilant. The MHRA’s warnings, combined with insights from physicians like Dr. Wood and guidelines from the CDC, offer a roadmap for safer medication management in extreme heat.
