Temperatures across the UK are expected to climb back above 30°C this weekend, prompting doctors to warn Britons taking certain medications about a potential 'perfect storm' of dangerous side effects.
Heatwave Forecast
The Met Office predicts a break from recent wet weather, with high pressure bringing drier and warmer conditions. Deputy Chief Meteorologist Greg Wolverson said: 'Saturday will see a more settled day across southern areas, with sunny spells and temperatures reaching 22-23°C. Northern areas may see some cloud and rain early on, but conditions improve later.'
'Sunday looks set to be widely dry across the UK, with further sunshine and temperatures rising. Many western parts can expect low 20s, with the warmest spots in southern England reaching 23-24°C, bringing a notably warmer feel.'
Met Office spokesman Dan Stroud noted that the south and southeast are likely to see the highest temperatures, with 'definitely a chance' of exceeding 30°C, especially on Monday.
Medications That Increase Heat Risk
Dr Hugh Coyne, a GP and co-founder of Coyne Medical, explained that several commonly prescribed medications can impair the body's ability to cope with heat. These include:
- Anticholinergic drugs: Some bladder medications and older antihistamines reduce sweating, a key cooling mechanism.
- Antipsychotics and lithium: These can affect the hypothalamus, the brain's temperature-control centre.
- Beta-blockers and calcium channel blockers: Used for anxiety and heart conditions, they limit blood flow to the skin, reducing heat dissipation.
- Diuretics: Increase dehydration risk by promoting fluid loss.
- Antidepressants and SSRIs: Can affect thermoregulation pathways.
Taking just one of these medications can make temperature regulation harder, but Dr Coyne emphasised that the 'greatest concern is often in people taking more than one, as the effects can be cumulative.'
Increased Risk of Heat-Related Illness
Dr Coyne warned that heatwaves create a 'perfect storm' for some patients. Dehydration can cause medications like lithium and digoxin to reach toxic levels in the blood, even at usual doses. Research suggests that people on psychiatric or cardiovascular medications face roughly double the risk of heat-related illness and death during extreme heat.
He noted that the strongest evidence for impaired temperature regulation relates to medications with a high anticholinergic burden, anti-Parkinson's drugs, and non-selective beta-blockers. Evidence for antidepressants and antipsychotics is less robust but still noteworthy.
Advice for Medication Users
Dr Coyne stressed: 'The key message is not to stop or alter prescribed medication without medical advice. Suddenly discontinuing treatment can carry significant health risks.'
Instead, he recommends:
- Staying cool and well hydrated.
- Avoiding prolonged sun exposure during the hottest part of the day.
- Seeking cooler indoor environments.
- Drinking fluids regularly, not just when thirsty.
For more advice on dehydration, consult the NHS website. Call 999 or go to A&E if you or someone else shows signs of shock, a serious complication of dehydration.
