On 7 August 2026, the Medicines and Healthcare products Regulatory Agency issued summer advice for people taking prescription or over-the-counter medicines. The regulator said some treatments can make it harder to stay hydrated, regulate body temperature or cope with sun exposure. (gov.uk) The notice sits within the MHRA's 'Summer-proof your health' campaign, launched on 9 July 2026 as a five-week public safety drive on medicines and medical devices in warmer months. The latest message does not tell patients to stop treatment; it points them instead towards practical precautions and professional advice. (gov.uk)
The MHRA lists three heat-related risk routes that are relevant to everyday prescribing. Diuretics can increase fluid loss and make dehydration more likely. Some antidepressants and antipsychotics can affect temperature regulation, while beta blockers may reduce the body's response to heat stress. (gov.uk) For policy and service audiences, the significance is that the warning concerns ordinary medicines use rather than rare edge cases. Symptoms may first appear at home or in community settings, which makes patient-facing advice and pharmacy counselling part of the safety response. (gov.uk)
The same MHRA notice also focuses on photosensitivity. It names certain antibiotics, including doxycycline and tetracycline, acne treatments such as isotretinoin and topical retinoids, the antifungal voriconazole, and DMARDs such as methotrexate and azathioprine. Proton pump inhibitors are linked to a very low risk of a lupus-like skin reaction triggered by sun exposure, and ibuprofen and naproxen may also increase sun sensitivity. (gov.uk) In practical terms, this means skin can burn faster or react more severely than expected. That is a relevant public message because several of the medicines listed are common repeat prescriptions or widely used over-the-counter products. (gov.uk)
The MHRA's recommended actions are deliberately simple. Patients are advised to check the leaflet for guidance on hydration and sun exposure, and to watch for dizziness, headache, unusual fatigue, confusion, reduced urination, or skin that becomes red, sore or blistered after sun exposure. (gov.uk) The regulator also points to routine protective steps: staying hydrated, avoiding the strongest sun in the middle of the day, and using protective clothing and sunscreen. Framed plainly, the campaign turns pharmacological risk into signs and actions that patients can recognise without needing specialist knowledge. (gov.uk)
A central line in the MHRA advice is that prescribed medicines should not be stopped during hot weather without clinical advice. Anyone unsure how heat or sunlight may affect a medicine is directed to a pharmacist or GP. (gov.uk) The first reference point is the patient information leaflet supplied in the pack. The MHRA Products service also publishes patient information leaflets and summaries of product characteristics online using the most up-to-date information held in a medicine's licence history, although the leaflet found online may not always match the copy in a pack if updates have been made. (products.mhra.gov.uk)
Where a side effect is suspected, the MHRA advises patients to speak to a doctor, pharmacist or nurse and to submit a report through the Yellow Card scheme. The scheme accepts reports from the public as well as healthcare professionals, and it covers medicines, vaccines, medical devices, blood products and e-cigarettes. (gov.uk) The regulator says these reports help it identify new safety issues, investigate patterns and, where needed, strengthen warnings or amend product information. The MHRA has also stated that NHS login can be used to create a Yellow Card account or access an existing one. (gov.uk)
For the wider system, the piece matters because it shows how seasonal communications feed post-market safety monitoring. Advice on hydration, sun exposure and medicine use is being tied directly to Yellow Card reporting, which is one of the MHRA's routes for spotting emerging concerns and updating safety information. (yellowcard.mhra.gov.uk) The overall message is narrow but important. Some common medicines can raise dehydration, heat stress or sun sensitivity risks in summer, but the regulator's answer is informed use, sensible precautions and reporting rather than self-directed changes to treatment. The MHRA is the UK executive agency responsible for regulating medicines and medical devices, and this campaign treats ordinary summer conditions as a medicines safety issue in their own right. (gov.uk)