THE MEDICINES AND HEALTHCARE PRODUCTS REGULATORY AGENCY (MHRA) has issued a reminder to patients in the UK to appropriately manage medication amid record-breaking summer temperatures.
The agency urged storage of medication out of direct sunlight in cool, dry places, awareness of heat-related illness symptoms, and potentially additional sun protection in line with medication guidance.
Alison Cave, Chief Safety Officer, MHRA, said: “Let’s face it – when there’s a heatwave, most of us are focused on getting outside and enjoying it while it lasts.
“But it’s easy to forget that medicines left in the heat – in cars, bags, or on sunny windowsills – might not work properly when you need them.
“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.”
Continuous Glucose Monitors
The MHRA warned that medical devices may be impacted by heat or humidity, with continuous glucose monitors (CGM) potentially giving less reliable readings if used or stored in hot conditions.
It recommended storing devices in cool, dry places, alongside checking for any temperature guidance for the specific device.
Upon the device failing to function as usual, patients were urged to run a control check or speak with a pharmacist.
Diuretics, Insulin, and Metformin
The advice also encouraged those taking diuretics to drink more water and stay cool to avoid dehydration.
Further, insulin and metformin can increase the risk of dehydration or make early symptoms harder to notice.
The MHRA warned that, overall, hot weather changes can impact the body’s response to medication, which can have adverse effects on the management of long-term conditions, such as diabetes.
Reference
GOV.UK. Don’t let this heatwave affect your medicines: three important tips from the MHRA. 2026. Available at: https://www.gov.uk/government/news/dont-let-this-heatwave-affect-your-medicines-three-important-tips-from-the-mhra. Last accessed: 2 July 2026.
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