St John Ambulance has issued a warning against storing certain medications in bathrooms or kitchens during the ongoing hot weather, as high temperatures and humidity can damage the drugs and impair the body's ability to cope with heat.
Which Medications Are Affected?
Commonly prescribed anti-seizure medications, including carbamazepine, sodium valproate, phenytoin, and lorazepam, can be physically affected by high temperatures and humidity, particularly if stored in warm locations. The charity advises avoiding bathrooms, kitchens, and cars for storing these medicines.
Anthony Freestone, Associate Clinical Director and Advanced Clinician in Emergency Care at St John Ambulance, told Saga Health Insurance: "As the UK faces another spell of extreme heat, it’s not just sunburn and dehydration we need to think about. Some medications can affect how your body responds to hot weather and sun exposure, and in a few cases, the heat can affect the medication itself."
How Heat Affects the Body and Medication
Freestone explained that some medicines can make skin more sensitive to sunlight, while others may affect how the body regulates temperature, sweats, stays hydrated, or controls blood flow. This can make it harder to cope with hot weather and may increase the risk of dehydration, heat exhaustion, or, in severe cases, heatstroke.
Regarding anti-seizure drugs, he noted: "It’s important to be clear: heat doesn’t directly trigger seizures in most people. The more likely route is indirect: dehydration, disrupted sleep from hot nights, and heat-affected medication can all lower seizure threshold in people who are already prone to them."
A 2023 Epilepsy Society survey found that six in 10 people with uncontrolled seizures noticed an increase in seizure activity during unusually hot weather.
Advice for Those on Heart and Blood Pressure Medication
While evidence directly linking heat, medication, and stroke risk remains limited, Freestone emphasised the importance of hydration for those taking cardiovascular medications. "A direct link between heat, medication and stroke risk is less well established in the UK evidence base, though dehydration is a recognised general risk factor for clot-related illness, and anyone on blood pressure or heart medication should take extra care to stay cool and hydrated," he said.
First Aid: The SAMPLE History
Freestone highlighted the importance of asking about medication when someone becomes unwell during hot weather. First aiders may use the "SAMPLE" history during a secondary assessment, which includes: Signs and symptoms, Allergies, Medication, Past medical history, Last meal/fluid intake, and Events leading up.
"Asking about medication as part of a secondary survey can help identify quickly whether heat-related medication issues, a missed dose, or an existing condition such as epilepsy or diabetes may be playing a part," he said.
Top Tips for Staying Safe
St John Ambulance advises: check whether hot weather or sun exposure could affect you; continue taking medication as prescribed unless advised otherwise; stay hydrated; keep out of direct sunlight during the hottest part of the day; seek shade; wear appropriate clothing; and store medication somewhere cool and out of direct sunlight. If you have any concerns, speak to your pharmacist, GP, or other healthcare professional.
