MHRA warns summer heat can affect your medicines

Sun cream, passport, chargers, tickets. Most of us have a packing routine in summer, but medicines are often treated like an afterthought. That is why the Medicines and Healthcare products Regulatory Agency, or MHRA, has issued a simple warning through GOV.UK: hot cars, warm suitcases and sunny rooms can all affect medicines in ways people may not notice until they need them. This matters because a medicine does not stop being important once it leaves the pharmacy. If it is stored in the wrong conditions, it may not work as well as expected. For anyone managing a long-term condition, travelling with contraception, or carrying inhalers for emergencies, that is not a small detail.

According to the MHRA, many medicines are meant to be stored below 25°C. When temperatures rise above that for long periods, especially in enclosed spaces, heat can reduce how well some medicines work. Parked cars, packed luggage, caravans and sunny windowsills can become much hotter than the weather forecast suggests. **What this means:** if a room feels warm to you, a bag left in direct sun or a boot left shut for hours may be warmer still. The risk is not only outside in a heatwave. It can happen indoors as well, especially near windows or heat sources.

Not every medicine needs the same care, and that is where people can get caught out. The MHRA says some medicines need refrigeration, while others should be kept at room temperature. The advice is especially important for medicines such as insulin, certain inhalers, creams used for skin conditions and some contraceptives. The same goes for some medical devices. Blood glucose monitors and insulin strips can also have specific storage needs. In other words, this is not only about tablets in a box. It is about the wider kit people rely on to stay well each day.

If you are wondering what to do in practice, the first step is very ordinary: read the patient information leaflet or check the packaging. That is where storage instructions are usually set out clearly. The MHRA also notes that patient leaflets are available online, which helps if the paper copy has gone missing at the bottom of a drawer or travel bag. At home, the safest rule is to think cool, dry and out of direct sunlight. That means not leaving medicines in bathrooms, on windowsills, or close to radiators and other heat sources. When you travel, it also means not assuming a suitcase, glove compartment or parked car is safe just because the medicine is zipped away.

There is a useful lesson here for summer habits. We often protect food, drinks and sun cream from the heat, but medicines can be forgotten because they look sturdy. In reality, some of them are sensitive to temperature and light, so out of sight is not the same as stored safely. **What to do if you are unsure:** speak to a pharmacist. That is the MHRA's advice if you do not know how a medicine should be stored, or if you think it may already have been exposed to too much heat. A quick conversation can help you work out whether it is still safe and effective to use.

If you suspect a medicine is not working as it should, the advice is not to guess. Speak to a pharmacist or doctor, especially if the medicine is important for managing symptoms or preventing complications. The MHRA also asks people to report suspected problems through its Yellow Card scheme, which is used to flag safety concerns about medicines and medical devices. This is one of those public-interest warnings that can sound small until it becomes personal. A few minutes spent checking storage instructions now could save you a great deal of worry later, particularly during hot weather and summer travel. The message from the MHRA is straightforward: looking after your medicines is part of looking after your health.