As UK weather maps forecast temperatures rising into the 30s Celsius again on July 27, peaking at 33C in western England and reaching 32C widely across southern areas, a pharmacist with over 35 years of industry experience has issued an urgent message about 10 common medicines that can affect how your body handles heat.
Which Medicines Increase Heatwave Risks?
Pharmacist Raj Patel listed the 10 medications on TikTok to his 95,000 followers: Olanzapine, Quetiapine, Chlorpromazine, Oxybutynin, Amitriptyline, Bisoprolol, Lithium, Sertraline, Methylphenidate, and Furosemide.
Patel explained: "Top 10 medicines that can affect sweating, hydration and temperature control during hot weather. These medicines do not necessarily make you hotter. But they may interfere with the warning systems your body uses to cope with heat – making overheating, dehydration or heat exhaustion harder to recognise."
How Each Medicine Affects the Body in Heat
He detailed how these drugs differ in their effects. Antipsychotics like Olanzapine, Quetiapine, and Chlorpromazine can interfere with the body's temperature-control systems. Oxybutynin and Amitriptyline have anticholinergic effects that reduce sweating, which is a primary way the body releases heat.
Bisoprolol, a beta-blocker, slows heart rate and may reduce normal cardiovascular responses during hot weather. Lithium requires special care because dehydration can increase lithium levels and raise toxicity risk. Sertraline may affect sweating and fluid balance in some people.
Methylphenidate can increase heart rate, reduce appetite, or make dehydration easier during prolonged activity. Furosemide, a water tablet, increases urine production and may contribute to dehydration, low blood pressure, and dizziness.
Who Is Most at Risk?
Patel advised that people aged 65 or over and those with heart or kidney problems face higher risk. Personal risk may also increase if you have diabetes, take several medicines, already struggle with dizziness or falls, exercise or stand outside for hours, drink alcohol in the heat, have vomiting or diarrhoea, or have been told to restrict fluids.
If you experience symptoms such as headaches, weakness, heavy sweating, or feeling faint, move somewhere cool and seek medical assistance.
Do Not Stop Medication Without Medical Advice
Patel stressed: "Do not stop any prescribed medicine because you have seen it on this list. Stopping medicines such as beta-blockers, antidepressants, antipsychotics or lithium without clinical advice can be harmful." He urged takers to "not panic" but instead "plan ahead."
The NHS advises continuing your prescriptions while taking extra precautions to stay cool, and monitoring for side effects like dizziness or increased confusion. Do not stop any medication without consulting your doctor.
NHS Tips for Staying Safe in Hot Weather
The NHS states hot weather can affect anyone, but some people are more vulnerable. Their tips include: keep out of the heat if possible; if you go outside, stay in the shade between 11am and 3pm, wear sunscreen, a hat and light clothes, and avoid exercise or activity that makes you hotter. Cool yourself down with cold food and regular cold drinks, drink extra fluids but avoid alcohol, caffeine and hot drinks, and take a cool shower or apply cool water to your skin or clothes. Keep your living space cool by closing windows, curtains and blinds during the day and opening them at night when the temperature outside has dropped. Electric fans can help if the temperature is below 35 degrees.
