As the United Kingdom experiences its third heatwave of the year with temperatures exceeding 34C (93.2F), health experts are issuing a critical warning about the impact of high temperatures on various medications. Storing medicines correctly is essential for maintaining their quality, effectiveness, and safety, according to the General Pharmaceutical Council.
Medicines requiring refrigeration should ideally be kept between 2C and 8C (35.6F and 46.4F). Most other medications recommended for room temperature storage should be kept between 15C and 25C (59F and 77F). Once temperatures rise above 25C (77F), the efficacy of certain drugs can diminish, particularly those stored in humid environments like kitchens, bathrooms, cars, or bags.
High temperatures can alter the chemical structure of medications. This can lead to creams separating, liquids evaporating, and capsules softening or melting. Alison Cave, chief medical officer at the Medicines and Healthcare products Regulatory Agency, noted that people often focus on enjoying hot weather and may forget that medicines left in the heat can become ineffective.
This concern is particularly relevant for weight-loss injections such as Mounjaro and Wegovy, which, while often stable at room temperature for up to 30 days, can degrade under excessive heat, thereby reducing their effectiveness. Similarly, insulin, vital for diabetes management, is susceptible to heat damage.
The UK Health Security Agency has issued an amber heat-health alert for most of England, indicating that hot weather is expected to persist. Other essential medications, including inhalers used for asthma and chronic obstructive pulmonary disease, can also be affected. The hydrofluoroalkane gas inside inhalers, which helps deliver the medication to the lungs, can expand in high temperatures.
Furthermore, devices used for monitoring health conditions can also be impacted. Blood glucose monitors, crucial for individuals with diabetes, may become less reliable in hot and humid conditions. A 2014 study highlighted that humidity levels as high as 83% could lead to inaccurate readings. Indoor humidity in parts of the UK can exceed this threshold during the summer months, with some cities experiencing levels above this critical point.
Experts urge the public to store medications in cool, dry places, away from direct sunlight and fluctuating temperatures and humidity, such as those found in kitchens and bathrooms. Simple steps to protect medicines include opening windows during cooler parts of the day and using fans to improve air circulation. For travel, insulated pouches or cool bags are recommended, but direct contact with ice packs should be avoided to prevent freezing, which can also damage medication.
Individuals with concerns about whether their medication has been compromised by heat exposure are advised to consult a healthcare professional. Adhering to specific storage instructions for each medication is paramount to ensuring its safety and effectiveness.