An urgent alert has been issued by a pharmacist regarding five specific types of medication that can potentially cause health complications during hot weather. People who take these medications should remain vigilant as temperatures are expected to rise this week, with Monday, June 30, predicted to be the hottest day of the year so far. The Met Office forecasts high temperatures of 21C tomorrow across much of Scotland, including in and around Glasgow and Aberdeen. But down south, two amber heat-health alerts have been issued as the mercury is to peak at 30C in London, with eastern England and the Midlands not far behind at 28C. Monday could see temperatures reaching an extreme 34C down south, marking only the fourth instance of such heat in June since the 1930s, reported the Mirror. But these scorching temperatures could interfere with certain common medications. On The Conversation website , Dipa Kamdar, Senior Lecturer in Pharmacy Practice at Kingston University, explained: “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 run into any problems with the heat. She reviewed various widely used medications in the UK, emphasising the need for users to act accordingly. Here are the five medications she mentioned. “[Some] antidepressants are believed to partly work by affecting neurotransmitter levels in the brain – primarily serotonin and noradrenaline. However, they may also affect other neurotransmitters. “For instance, TCAs can block acetylcholine, a neurotransmitter important for sweating. This may cause some patients to sweat less. On a hot day, this could make it hard to cool down. “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.” “Someone taking an antipsychotic might not feel overheated or thirsty when it’s hot out. This can cause low blood pressure and reduced heart function. “The body then tries to compensate by narrowing the blood vessels and holding in heat. This in turn reduces sweating and makes it harder to cool down properly. “Additionally, antipsychotics have anticholinergic properties. This means they block the action of acetylcholine, making it harder to sweat.” The expert 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 鈥 such as the amphetamines used for ADHD 鈥 affect many brain chemicals, including dopamine and noradrenaline. This can increase body temperature, boost metabolism and change how the body sweats 鈥 all of which can make it harder to cool down, especially when exercising or in hot weather. This can also potentially lead to dehydration, overheating or even heatstroke. Stimulants may also reduce the feeling of tiredness, which can cause people to overexert themselves without realising. Ms Kamdar said: 鈥淲arm temperatures cause the body鈥檚 blood vessels to dilate in order to help us cool off. But this action means insulin is absorbed into the bloodstream faster as there鈥檚 enhanced blood flow to the area where insulin is injected 鈥 making blood sugar drop more quickly. “This can lead to hypoglycemia (low blood glucose level), which may lead to dizziness, shaking, sweating, irritability and even potentially loss of consciousness or seizures. 鈥淗eat can also degrade insulin, reducing its effectiveness and making it unsafe. This is why insulin should be stored in the fridge until use 鈥 especially in summer. Damaged insulin will change appearance 鈥 turning cloudy or changing colour.鈥