The Met Office has issued a rare amber heat warning for parts of Wales and South England, effective from Monday, June 22 to Thursday, June 25. The warning highlights that vulnerable individuals, including those taking beta blockers or metformin, are at increased risk of heat-related illnesses.
Medications Increase Heat Sensitivity
Beta blockers, commonly prescribed for heart conditions and high blood pressure, can slow heart rate and impair the body's ability to cool itself, leading to quicker overheating. The Medicines and Healthcare products Regulatory Agency (MHRA) warns that blood pressure medicines, including ACE inhibitors, beta blockers, and calcium channel blockers, can make temperature regulation harder during sudden hot spells.
Metformin, insulin, and other diabetes medications can increase dehydration risk and mask early symptoms. Untreated dehydration can lead to kidney issues, seizures, or brain damage. Symptoms of dehydration include thirst, headache, dizziness, dark urine, and dry mouth.
Research Shows Increased Heart Attack Risk
A 2022 study found that people using beta blockers or antiplatelet medications may be more likely to have heart attacks during hot weather. Beta blockers specifically showed a 65% increase in the association between hot weather and heart attacks.
Official Guidance and Precautions
Users of beta blockers or metformin should not stop their medication but should act quickly if they experience signs of dehydration or heat-related illness. The MHRA advises reading patient information leaflets or consulting a pharmacist about sun sensitivity as a side effect.
The amber warning, the most extreme issued by the Met Office in four years, runs from 1am on June 22 to 23:59pm on June 25. Officials warn of widespread impacts on people and infrastructure, with some possibly needing to change work patterns. The general population may also experience adverse health effects such as sunburn or heat exhaustion.
