Essential Heat Warning for Millions Taking Blood Pressure Medicines in the UK

Why people taking ACE inhibitors, beta blockers and other medicines need extra care during hot weather

Millions of people across the UK who take prescription medicines have been reminded to take extra precautions during periods of hot weather. Health officials have warned that high temperatures can affect both how medicines are stored and how the body responds while taking certain treatments.

The Medicines and Healthcare products Regulatory Agency (MHRA) has issued advice for people using commonly prescribed medicines, including ACE inhibitors and beta blockers. These medications are widely used to manage conditions such as high blood pressure, heart problems and other long-term health conditions.

As temperatures rise during summer heatwaves, patients are being encouraged to check how they store their medicines and understand whether their medication could increase their risk of heat-related problems.

Which medicines are affected by hot weather?

Many commonly prescribed medicines can be affected by extreme heat. ACE inhibitors and beta blockers are among the main groups highlighted by health officials.

ACE inhibitors, including medicines such as ramipril, enalapril and captopril, are often prescribed to help control blood pressure and support people with heart conditions.

Beta blockers, including bisoprolol, propranolol and atenolol, are also frequently prescribed for heart-related conditions, high blood pressure and other medical concerns.

The MHRA has also advised people taking other types of medication to remain aware during very warm weather. These include:

• Some diabetes medicines, including insulin and metformin
• Diuretics, also known as water tablets, such as furosemide
• Certain antidepressants and antipsychotic medicines
• Some antibiotics and skin treatments that can increase sensitivity to sunlight

People taking these medicines should follow medical advice and speak with a pharmacist or healthcare professional if they are concerned.

How does heat affect medication?

Most medicines should be stored in a cool, dry place, usually below 25C unless the packaging states otherwise. During hot weather, indoor temperatures, cars and direct sunlight can create conditions that may damage some medicines.

Heat can reduce the effectiveness of certain medications by affecting their active ingredients. Medicines that need refrigeration are especially vulnerable if they are exposed to high temperatures for long periods.

Leaving medication inside a parked car, near a sunny window or inside a bag exposed to sunlight could affect its quality.

The MHRA advises people to check medicine labels and patient information leaflets for specific storage instructions.

Why some medicines can make heat harder to manage

Hot weather naturally causes the body to lose more water through sweating. However, some medicines can make it more difficult for the body to regulate temperature or recognise signs of dehydration.

For example, some blood pressure medicines can affect the body's response during sudden temperature increases. ACE inhibitors may reduce thirst signals, meaning some people may not realise they need to drink more fluids.

Beta blockers can also affect how the body responds to heat by influencing heart rate and circulation.

Diuretics can increase fluid loss because they encourage the body to remove more water through urination. This can raise the risk of dehydration during hot conditions.

People with existing health conditions, including heart disease, kidney problems or diabetes, may need to take extra care during heatwaves.

Signs of dehydration and heat-related illness

Recognising the early signs of dehydration is important, especially for older adults and people taking regular medication.

Common symptoms can include:

• Feeling dizzy or lightheaded
• Headaches
• Unusual tiredness
• Confusion
• Darker urine
• Increased thirst

If someone feels unwell during hot weather, they should move to a cooler area, drink fluids slowly and seek medical advice if symptoms continue or become worse.

Severe heat-related illness can become dangerous quickly, particularly among vulnerable groups.

Tips to protect medicines during summer

The MHRA recommends several simple steps to keep medicines safe during periods of high temperatures:

Store medicines correctly

Keep medication in a cool, dry location away from direct sunlight. Avoid storing medicines in places that become hot, such as cars, window ledges or outdoor areas.

Check storage instructions

Different medicines have different requirements. Always follow the guidance on the packaging or speak to a healthcare professional if you are unsure.

Avoid leaving medicines in hot vehicles

A car can become extremely hot even when outdoor temperatures are moderate. Medicines left inside may be exposed to damaging levels of heat.

Stay hydrated

Drink enough fluids during hot weather and pay attention to signs that your body may be struggling with the temperature.

Take care in the sun

Some medicines can make skin more sensitive to sunlight. This may increase the chance of sunburn, so extra protection such as sunscreen, shade and suitable clothing may be needed.

When should you contact a healthcare professional?

People should not stop taking prescribed medication without medical advice. If you are worried about how your medicine may interact with hot weather, contact your pharmacist, GP or healthcare provider.

A healthcare professional can provide guidance based on your individual circumstances and explain whether any extra precautions are needed.

Final thoughts

Summer heat can create additional challenges for millions of people who rely on regular medication. While most people can continue taking their prescriptions safely, it is important to understand how temperature, hydration and medicine storage can affect health.

Simple steps such as storing medicines properly, drinking enough fluids and recognising warning signs can help reduce the risks during hot weather.

Anyone taking ACE inhibitors, beta blockers or other long-term treatments should remain aware of official health guidance and seek advice if they have concerns.

Sources

Information for this article is based on guidance from the Medicines and Healthcare products Regulatory Agency (MHRA) regarding medicine safety during periods of extreme heat, alongside general public health advice from UK healthcare organisations.

Disclaimer

This article is for general information purposes only and does not replace professional medical advice. Medication requirements vary from person to person. Do not stop, change or adjust prescribed medicines without speaking to a qualified healthcare professional.