A pharmacist has warned anyone on these drugs they should take action to protect themselves as the temperatures rise this week
People enjoy the hot weather on Formby beach. Anyone taking five kinds of medication is being asked to take steps to prevent health issues(Image: Liverpool Echo)
A health warning has been sounded for individuals on five different medications, as they could experience adverse effects in the rising temperatures. A pharmacist has advised those on these drugs to take precautions as the mercury climbs this week, with Monday anticipated to be the warmest day of the year so far.
The UK is set to bask in another surge of heat on Sunday, with an amber heat health alert still in place. Forecasts from the Met Office suggest highs of 30C in London, 28C in the east of England, and 28C in the Midlands.
Monday’s temperatures might peak at 34C, a level of heat not often seen in June since the 1930s.
Dipa Kamdar, Senior Lecturer in Pharmacy Practice at Kingston University, highlighted on The Conversation website that: “The body uses several mechanisms to regulate temperature: sweating, blood flow to the skin and fluid balance. But some commonly prescribed drugs interfere with these processes, making it harder to stay cool.”
She emphasised that people should keep taking the medications – but that they need to take measures to ensure they don’t have an issue.
She examined a range of medications widely used across the UK, noting the importance of taking extra care.
Antidepressants
Ms Kamdar pointed out that two particular types of antidepressants – selective serotonin reuptake inhibitors (SSRIs) and tricyclics (TCAs) – ‘may make summer harder to cope with’. She explained: “They could even cause heat intolerance due to how they affect the body’s ability to sweat.”
Both these antidepressants are believed to partly work by affecting neurotransmitter levels in the brain – primarily serotonin and noradrenaline. This could result in some patients sweating less, which on a hot day, could make it difficult to cool down.
Ms Kamdar said: “Since sweating is a key cooling mechanism, any disruptions to this process can lead to heat-related illness. Excess sweating may also cause dehydration if fluids aren’t replaced.”
Antipsychotics
Ms Kamdar explained: “Antipsychotics are used to treat psychosis, which can occur in schizophrenia and bipolar disorder. They do this by blocking the neurotransmitter dopamine – which in turn affects levels of the neurotransmitter serotonin. This can disrupt the hypothalamus’s ability to sense and respond to body temperature changes.
“As a consequence, someone taking an antipsychotic might not feel overheated or thirsty when it’s warm outside. This can result in low blood pressure and diminished heart function.
“The body then attempts to compensate by constricting the blood vessels and retaining heat. This consequently reduces perspiration and makes it more challenging to cool down effectively.”
Heart medications
Beta-blockers lower heart rate and reduce how forcefully the heart pumps. However Ms Kamdar said this can limit blood flow to the skin – making it harder for the body to release heat on hot days.
She added: “Diuretics are also commonly used in the treatment of high blood pressure or heart failure. But as these drugs increase urine output, this may lead to dehydration and electrolyte imbalances during hot weather.
“With less fluid available, the body may struggle to sweat properly. If you become severely dehydrated, you might actually stop feeling thirsty. Blood pressure can also drop, which may cause dizziness or fainting – especially when standing up.”
Ramipril and losartan, also used to manage blood pressure, can increase the risk of dehydration as well, she said. “These drugs block a system in the body that helps control blood pressure, fluid balance and thirst. This may reduce your natural urge to drink, increasing dehydration risk when it’s hot.”
Stimulants
Like the amphetamines prescribed for ADHD – influence numerous brain chemicals, including dopamine and noradrenaline. These effects can raise body temperature, accelerate metabolism, and alter the body’s sweating mechanism, making it more challenging to cool down, especially during physical activity or in hot weather.
This could potentially lead to dehydration, overheating, or even heatstroke. Stimulants may also suppress feelings of fatigue, causing individuals to overexert themselves without recognising the danger.
Insulin
Ms Kamdar explained: “Warm temperatures cause the body’s blood vessels to dilate (widen) to aid in cooling off. However, this process results in faster absorption of insulin into the bloodstream due to increased blood flow to the area where insulin is injected – causing blood sugar levels to drop more rapidly.
“This can result in hypoglycaemia (low blood glucose level), potentially causing symptoms such as dizziness, shaking, sweating, irritability, and even loss of consciousness or seizures.
“Heat can also degrade insulin, reducing its effectiveness and making it unsafe. This is why insulin should be stored in the fridge until use – especially in summer. Damaged insulin will change appearance – turning cloudy or changing colour.”
To avoid heatstroke, Ms Kamdar suggests several preventative measures for those on common prescription drugs:
- Always check labels for storage instructions. Avoid leaving medications in hot places, such as in cars or on windowsills.
- Insulin isn’t the only drug affected by heat – inhalers and EpiPens can also malfunction or become less effective.
- Stay hydrated when it’s hot – unless your doctor has advised otherwise. Dehydration can actually worsen the effects of many medicines.
- For example, anti-inflammatory painkillers (such as ibuprofen) are more likely to cause kidney problems and bipolar medicines (including lithium) can become toxic if you’re dehydrated.
- Avoid peak heat hours and stay in cool environments when possible. Watch for warning signs of heat-related illness – such as dizziness, confusion, nausea or excessive sweating.
- Don’t stop taking your prescriptions medication without medical advice. If it’s affecting your ability to cope with the heat, speak with your doctor or pharmacist.
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