As the UK enters the heart of summer – with temperatures rising and families holidaying – the Medicines and Healthcare products Regulatory Agency (MHRA) is reinforcing essential safety advice for anyone using medicines or medical devices. The aim is to help everyone enjoy the summer safely, while ensuring their healthcare routine stays effective. 

Dr Alison Cave, Chief Safety Officer at the MHRA, commented: 

“When the sun comes out and the thermometer rises, it’s easy to forget that heat can affect medicines and medical devices, and that some treatments can change how you respond to sun and heat. These refreshed summer tips are vital to help people stay safe and well throughout the summer.” 

1. Store medicines below 25oC 

• Avoid leaving medicines in direct sun, hot cars, travel bags, or on sunny windowsills – temperatures can easily exceed safe storage limits and degrade tablets, inhalers, insulin, EpiPens and more.  

• If you spot changes in smell, colour, texture, or performance of your medicines, consult a pharmacist.  

• While travelling, keep your medicines in a cool bag or stay in temperature-controlled environments. 

2. Check your medicines and devices in the heat 

• Even well-sealed medical devices – like blood glucose monitors – can misread if exposed to excessive heat or humidity.   

• Stay cool, keep devices dry, and run periodic control checks. 

• Be alert during heatwaves: some medicines can worsen dehydration or impair temperature regulation, including diuretics, blood pressure drugs, diabetes treatments, antipsychotics, and stimulants.  

3. Prioritise hydration and heat awareness 

• Heatstroke and dehydration can happen fast. Watch for dizziness, confusion, headaches or dark urine, especially if you’re on medication that affects fluid balance, such as a diuretic. 

• Drink water regularly, find shade or cool spaces, and avoid peak sun.  

4. Be sun-smart with sun-sensitising medicines 

• Several medicines – such as methotrexate, certain antibiotics, diuretics, antidepressants, acne or eczema treatments, and even painkillers like ibuprofen –can increase sun sensitivity, leading to severe sunburn and blistering.  

• Use a high-SPF sunscreen, wear protective clothing, and avoid midday sun (11 am – 3 pm). 

5. Hay fever alert – stay informed   

• Avoid unlicensed treatments like Kenalog hay fever injections, which are licensed as a medicine for other conditions, but not for the treatment of hay fever. The benefits of using it to treat people with hay fever have not been shown to outweigh the risks.     

6. Be aware of implanted medical devices when travelling 

• For those with implants (e.g. pacemakers), carry your implant ID card at airport security. Most body scanners are safe, but be aware of hand-held wands and device-specific device advice.  

7. Report safety issues via the Yellow Card scheme 

• If exposure to heat, sun, or medications seems to have affected your medicine, report it via the MHRA’s Yellow Card scheme – the UK system for flagging medicine/device safety concerns. 

• Prompt reporting helps the MHRA identify adverse reactions early and act to protect public health.  

Notes to editors  

1. Report any concerns through the MHRA Yellow Card scheme, which can be accessed at https://yellowcard.mhra.gov.uk/ 

2. The Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for regulating all medicines and medical devices in the UK by ensuring they work and are acceptably safe.  All our work is underpinned by robust and fact-based judgements to ensure that the benefits justify any risks.  

3. The MHRA is an executive agency of the Department of Health and Social Care.  

4. For media enquiries, please contact the newscentre@mhra.gov.uk, or call on 020 3080 7651.