UK heatwave: warnings issued for several common medications and side effects

Certain medications, like GLP-1s, antidepressants, and beta-blockers, can increase your risk for heat-related illnesses. Image Credit: Evgeniya Pavlova/Getty Images Certain types of medications can make people more prone to heat-related illness. These include antidepressants, GLP-1 medications, and beta-blockers.  They can cause dehydration, reduced sweating, and problems regulating temperature. It’s important to keep cool and drink plenty of water during hot weather, and if you experience symptoms of heat-related illness, seek medical help right away.   July is often the hottest month of the year, with heatwaves becoming increasingly more common. Last year was the third-warmest July on record, with July 2024 being the hottest month ever recorded. While the summer sun and warmer temperatures are often enjoyable, for those who take certain medications, the warmer months may contribute to serious health issues.  “[People] are all aware of the risks of overheating, dehydration, and sunburn. But [they] should all be more aware of how medications can cause intolerance to summer heat,” said David Cutler, MD, board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA.  According to the Centers for Disease Control and Prevention (CDC), medications can contribute to heat sensitivity in various ways, including:  reduced sensations of thirst interference with thermoregulation impaired sweating reduced cardiac output electrolyte imbalance cognitive impairment Here are 10 common medications that can be affected by hotter weather, and some tips for staying safe.  Antidepressants Certain types of antidepressants, like selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs), can increase heat sensitivity.  Heat sensitivity, or heat intolerance, occurs when you’re unable to regulate your body temperature effectively.  “The most obvious effects of heat intolerance are seen in those taking medications which decrease sweating,” said Cutler. Antidepressants may disrupt typical sweating patterns. This may lead to either hyperhidrosis (excessive sweating) or anhidrosis (reduced sweating) in warmer weather. A disruption in sweating patterns can make it difficult for your body to cool itself, leading to heightened sensitivity to heat.  Research from 2022 noted that these types of antidepressants can raise your core body temperature to 106° F (41°C). This can increase your risk of heat exhaustion and heatstroke.  It may be useful for you to make a heat safety plan with your healthcare professional and share it with your loved ones.  Antipsychotics Antipsychotic medications can also affect how your body reacts to the heat. Like antidepressants, antipsychotics can interfere with your body’s thermoregulation. They can also alter your perception and compromise your ability to sense and respond to heat.  Certain antipsychotic medications, like lithium, can lead to dehydration-induced drug toxicity.  Signs of lithium toxicity Signs of lithium toxicity include:  dizziness tremors unsteadiness lethargy slurred speech confusion To prevent drug toxicity in hot weather, it is important to drink plenty of water and other fluids to stay hydrated. If you believe you are experiencing signs of lithium toxicity, you should contact a healthcare professional right away.  Beta-blockers Beta-blockers can make you more sensitive to heat.  Since they help the heart beat more slowly and with less force, these medications are most often used to treat irregular heartbeat and high blood pressure, but they have a range of other applications, including the treatment of anxiety disorders. Some common examples include metoprolol and propranolol. Beta-blockers can impair thermoregulation and elevate core body temperature. The American Heart Association (AHA) notes that these medications can exaggerate your body’s reaction to heat.  It is important that you continue to take medications as prescribed and speak with your healthcare professional about potential side effects during the hotter months.  ACE inhibitors Angiotensin converting enzyme (ACE) inhibitors are medications that are primarily used to treat high blood pressure.  These medications can affect your body’s temperature regulation, increasing your risk of heat-related illness. They can also suppress your natural thirst response.  It is important to take proper precautions to stay cool and to drink plenty of fluids to prevent dehydration.  Diuretics Cutler told Healthline that diuretics force fluid through the kidneys and out of the body to control high blood pressure and heart failure. These medications could cause dehydration, a potentially grave danger in hot weather. Diuretics help increase the amount of water and salt that you expel from your body through urine. This increased fluid loss, along with increased sweating during warmer weather, can lead to dehydration.  This means it is important to drink more fluids during hot weather, especially when taking these medications.  Diuretics may also make you more susceptible to sunburn, so proper sun protection is extra important during the hot summer months.  Insulin Diabetes can affect your sweat glands and your body’s ability to cool itself. The condition can also increase your risk of dehydration.  High temperatures also cause your body to absorb insulin more quickly. This can lead to an increased risk of hypoglycemia (low blood sugar).  The CDC suggests that people with diabetes may need to test their blood sugar levels more often in warmer weather. These individuals may also need to adjust their insulin dose and what they eat or drink.  Metformin Jennings noted that taking diabetes medications like metformin or GLP-1s can increase your risk of dehydration. He stated that this may be due in part to the fact that when people eat less, they also typically drink less.  Metformin may also make it more difficult to recognize the signs of dehydration.  While it is rare, this medication can also increase the risk of and lead to lactic acidosis, especially in people with kidney issues. This may be due to severe dehydration.  GLP-1s GLP-1 medications, like Ozempic, Wegovy, and Mounjaro, may increase your risk of heat-related illnesses.  These medications help suppress your natural thirst cues, causing you to naturally drink fewer fluids. This can lead to dehydration, especially in hotter weather.  GLP-1 medications can also delay stomach emptying and cause nausea. These can both cause you to drink less, increasing your risk of dehydration.  These medications may lower blood pressure in some people, leading to dizziness and fainting. This can be further compounded by warmer weather, which can cause you to sweat more and lose more fluids.  Signs of dehydration Signs of dehydration may include:  fatigue low urine output dark colored urine dry skin or cracked lips headache dizziness or light-headedness heart palpitations low blood pressure altered mental status or poor concentration Stimulants Stimulant medications, such as amphetamines for attention deficit hyperactivity disorder (ADHD), can greatly affect your body during hotter weather.  These medications are associated with thermoregulatory dysfunction. This means they affect how your body controls its temperature.  There is some evidence to suggest that this can increase the risk of heat-related illness, especially in athletes with ADHD who take these medications.  “Stimulants also decrease appetite and result in less fluid intake,” Jonathan Jennings, MD, board certified internist with Medical Offices of Manhattan, told Healthline.  This can lead to dehydration, so it is important to drink plenty of fluids.  Research from 2024 found that these medications may reduce the risk of heat-related illness in some people. However, more research is needed.  You should speak with your healthcare professional about heat-related risks with these medications.  Anticonvulsants Some anticonvulsant medications, such as zonisamide and topiramate, may reduce the amount you sweat.  Older research shows that this may be more pronounced in children who use these medications. People taking anticonvulsants should try to avoid heat and humidity as much as they can. 

Why taking antidepressants "stops people functioning" in heatwaves  BBCHow to keep your medicines safe during hot weather  The Conversation10 Medications Linked to Heat-Related Health Risks  HealthlineRamipril and bisoprolol users issued caution by UK government for this week  Wales OnlineAmid heat wave, doctors warn of health risks for people taking GLP-1 drugs  Good Morning America

People taking antidepressants or antipsychotics are more prone to overheating this summer, experts say

The heat can have dangerous side effects on certain medications.

GP warns millions at risk of deadly fat jab mistakes in heat…when to dial 999  The SunUK heatwave: Five medications that can affect how your body regulates temperature  The IndependentFive medications 'could cause big problems' in heatwave as pharmacist issues warning  Wales OnlineOn antidepressants? Doctors are warning of hot weather specific side effects to be careful of  CosmopolitanNHS pharmacist issues stark warning to Brits using Mounjaro during hot weather  The Sun