The UK is currently experiencing another heatwave, with temperatures set to reach a sweltering 36C in some parts – but some popular prescription drugs and supplements could be dangerous in the heat
The UK has been hit with another scorching heatwave, with temperatures set to soar to 36C in some parts of the country. But while we attempt to keep cool and soak up the sunshine, a warning has been issued over the potential dangers of taking some prescription drugs and supplements during a heatwave.
Prescription medications are issued by a healthcare professional while supplements can be purchased over the counter, online or in a high street store.
While they can both be taken all year round, extra care is needed during the warmer weather as increased sun exposure can cause serious health issues, and can even be fatal. It comes after a heatwave forecast with maps revealing the exact date a 39C heat plume will scorch the UK.
READ MORE: UK heatwave: Brits to be hotter than BALI as 35C blast hits homeREAD MORE: ‘I dismissed pain as a stitch before disease took everything’
Guidance from the UK Health Security Agency (UKHSA) states: “Medications commonly taken for chronic conditions, such as diuretics, beta-blockers, or drugs used to treat mental health issues (like antipsychotics and common antidepressants like SSRIs), can also alter the body’s ability to cool itself or keep fluids, making people even more susceptible to complications.
“It is important to understand how your medication affects your body’s response to heat and reread any instructions or speak to your doctor or pharmacist if you have any concerns.
“In this way, hot weather doesn’t just present a risk of heat-related illness, but can act to worsen existing health conditions, an often overlooked but critical part of why some people may suffer more than others during heatwaves.”
Here’s everything you need to know, and which medications and supplements can have dangerous side effects during the hot weather…
Diuretics
Diuretics, a type of medication often prescribed to treat heart failure, high blood pressure, or kidney disease, can cause issues during a heatwave. These drugs increase urination frequency, which, while beneficial for these conditions, can lead to dehydration or an imbalance of electrolytes like magnesium, potassium, or salt.
This makes it more difficult for the body to regulate its temperature. Those using this medication are advised to maintain high water intake and stay alert for signs of dehydration like headaches, dizziness, dark coloured urine and feeling thirsty.
ACE inhibitors
Another medication type that can spell trouble in hot weather, ACE inhibitors are typically prescribed for high blood pressure patients. As the mercury rises, those taking them may be more prone to fainting or falling.
Additionally, this medicine cloaks the sensation of thirst, making it harder to recognise when dehydration may be setting in.
Beta-blockers
Beta-blockers can also pose a risk during the sweltering heat. Not only do they heighten the odds of fainting and losing your footing, but they also hinder the body’s sweating ability.
This poses concerns about overheating due to insufficient cooling. This side effect isn’t unique to Beta-blockers; some antipsychotic medications used for mental health illnesses such as haloperidol, olanzapine and risperidone also dim the sweating capacity.
Antidepressants
Certain antidepressants, including SSRIs, can become dangerous during hot weather as they often heighten sweating and suppress thirst, making users more prone to dehydration-related complications.
This does not mean you should stop taking antidepressants if you have been prescribed them – because a sudden withdrawal from these medications can be incredibly dangerous.
Instead, you should take your prescription as your GP has directed and continue that normal – but take extra precautions surrounding the heat.
This should include avoiding going outside or doing exercise during the hottest hours of the day – between 11am and 3pm – and sticking to the shade as much as possible.
You should also avoid drinking any alcohol, because this is dehydrating, and make sure you are drinking plenty of water, as well as opting to wear loose breathable fabrics like cotton and linen during a heatwave.
Levothyroxine
Those taking thyroid medication, such as Levothyroxine, for an underactive thyroid could also be impacted in the heat. These medications can elevate body temperature and make it more difficult to effectively regulate body temperature.
Methylphenidate/Amphetamine
Stimulants such as amphetamines and medication used to treat attention deficit hyperactivity disorder (ADHD), such as methylphenidate, may also heighten the risk of heat-related illnesses by interacting with the central nervous system and brain.
The risks aren’t confined to prescription medication either, as certain over-the-counter medicines can also make you more vulnerable to heat-related illnesses, such as the sleeping pill Nytol (Diphenhydramine), and hayfever medicines like Phenergan and Sominex (Promethazine).
Vitamin D
When it comes to supplements, vitamin D is a common one taken during the autumn and winter months when the UVB rays are lacking. But taking vitamin D during the summer, could cause more harm than good.
Chemist Click Pharmacist Abbas Kanani told the Sun: “This could put you at increased risk of vitamin D overdose. Vitamin D overdose can happen if you’re using supplements in high doses, as well as getting extended periods of sun exposure.”
The NHS also warns that adults and children aged 11 to 17 should not take more than 100 micrograms (4,000 IU) of vitamin D per day, as it “could be harmful”. Children under 10, should have no more than 50 micrograms (2,000 IU) per day.
Vitamin A
Some people take vitamin A supplements to support vision, boost the immune system, and maintain healthy skin and mucous membranes.
Vitamin A is a retinol and is needed for vision in dim light and to keep the immune system working properly to help fight infection and illness. It is also important to help keep the skin and some parts of the lining of the body, such as the nose healthy.
However, Dr Kanani warned that a high-dose vitamin A can increase “skin sensitivity to sunlight”, which can lead to sunburn. Sun sensitivity can also cause “burning, blistering, and dark patches on the skin (called hyperpigmentation).”
Vitamin B3
Also known as nicotinic acid, this B vitamin is key in converting food into energy for our bodies. It also supports the health of the nervous system, digestive system, and skin. That’s why you’ll often find niacin in your daily multivitamins, although most of us get enough from our diet.
Niacin can be used to treat various lipid disorders, including metabolic syndrome, diabetes mellitus, hypertriglyceridemia, and isolated low HDL cholesterol. Side effects may include flushing, red face or neck, diarrhoea, headache, upset stomach, and skin rash.
It can also cause flushing and increased heat sensitivity, which can be detrimental during the warmer months.
What to do if you notice signs of dehydration or heatstroke
“Dehydration can cause dizziness, headaches, tiredness, confusion, and dark urine. This is particularly dangerous for older adults, young children, and people with heart or kidney conditions,” the Medicines and Healthcare products Regulatory Agency warns.
Offering advice to anyone affected, the agency states: “If you start to feel unwell in the heat, move somewhere cooler, sip water slowly, and seek medical advice if you don’t feel better quickly.”
