An amber extreme heat warning has been issued across parts of England and Wales as temperatures are forecast to peak around 34°C, with potential for higher readings on Monday and Tuesday. High humidity and tropical nights, where temperatures remain above 20°C, have triggered heat health alerts from the UK Health Security Agency (UKHSA).
Five Medications That Increase Risk
Dipa Kamdar, a Senior Lecturer in Pharmacy Practice at Kingston University, has identified five common types of medication that can severely disrupt the body's natural cooling mechanisms, drastically raising the risk of heatstroke, low blood pressure, and severe dehydration. Health officials stress that patients must not stop taking prescribed medication but should take immediate preventative measures.
Antidepressants
Kamdar explained that commonly prescribed antidepressants like Selective Serotonin Reuptake Inhibitors (SSRIs) and Tricyclic Antidepressants (TCAs) alter brain chemistry, directly impairing the body's internal thermostat. By shifting neurotransmitters like serotonin, these drugs can severely limit a patient's ability to sweat, making it difficult for the body to cool down in 30°C weather.
Antipsychotics
Used to manage conditions like schizophrenia and bipolar disorder, antipsychotics block dopamine and alter serotonin levels. This process disrupts the hypothalamus, the brain's temperature-regulating centre. Consequently, patients may lose the ability to sweat effectively or fail to realize they are overheating or thirsty, leading to low blood pressure and dangerous heat retention.
Heart and Blood Pressure Medications
Cardiovascular drugs pose a multi-pronged threat. Beta-blockers lower heart rate and reduce pumping force, restricting blood flow to the skin and preventing heat escape. Diuretics, used for heart failure and high blood pressure, increase urine output, accelerating dehydration and electrolyte imbalances in severe heat. Other drugs like Ramipril and Losartan disrupt fluid-balancing systems, suppressing the natural urge to drink and increasing heat exhaustion risk.
Stimulants
Medications often prescribed for ADHD, such as amphetamines, raise baseline body temperature, accelerate metabolism, and impair sweating. Because stimulants can mask physical feelings of exhaustion, individuals risk overexerting themselves in high heat without realizing their body is reaching a critical breaking point.
Insulin
People using insulin may experience dizziness, shaking, sweating, or seizures during heatwaves. Hot temperatures cause blood vessels to dilate, increasing blood flow to injection sites and leading to faster insulin absorption. This causes blood sugar levels to drop more rapidly, resulting in hypoglycaemia. Extreme heat can also degrade insulin, turning it cloudy and unsafe to use.
Tips for Medication Users During the Heatwave
Kamdar advises preventative action to ensure safety while continuing medication. She recommends: always check labels for storage instructions; avoid leaving medications in hot places like cars or windowsills; remember that insulin, inhalers, and EpiPens can malfunction or become less effective in heat; stay hydrated unless a doctor advises otherwise, as dehydration worsens medication effects—for example, anti-inflammatory painkillers like ibuprofen can increase kidney problems, and bipolar medicines like lithium can become toxic if dehydrated; avoid peak heat hours and stay in cool environments; watch for warning signs of heat-related illness such as dizziness, confusion, nausea, or excessive sweating; and never stop prescribed medication without medical advice—if it affects heat tolerance, speak with a doctor or pharmacist.
