From 115 degrees in Wichita Falls, Texas, to 104.4 degrees in London, England, record high temperatures are scorching cities worldwide this summer, putting additional demand on healthcare professionals. Factors such as age, weight, pregnancy status, or occupation can impact a person’s ability to deal with extreme heat and increase their risk of developing a heat-related illness such as syncope, heat exhaustion, rhabdomyolysis, or heat stroke, according to the CDC. Still, healthcare professionals should also consider the effects of the medications a patient is taking when evaluating their risk.
Research examining the link between heat-related illness and medication is limited. However, potential temperature-related adverse effects with medications can occur, according to Aaron Bernstein, interim director of the Harvard T.H. Chan School of Public Health’s Center for Climate, Health and the Global Environment in a 2020 article for The Washington Post. Whether it’s a reduction or an increase in the body’s ability to sweat, reduced thirst recognition, diuresis and electrolyte imbalance, or decreased cardiac output, nurses should be aware of medications that could interfere with normal thermoregulatory functions and make patients more susceptible to overheating and heatstroke during the summer months, per a 2015 article “Medicines can affect thermoregulation and accentuate the risk of dehydration and heat-related illness during hot weather” in Journal of Clinical Pharmacy and Therapeutics.
Blood Pressure: Thiazide diuretics, such as chlorthalidone and hydrochlorothiazide, used to treat high blood pressure, increase the amount of water and salt passed through urination and can cause dehydration. Beta-blockers such as metoprolol and propranolol can reduce blood flow to the skin and inhibit sweating, a key component in controlling body temperature, according to Dr. Wafi Momin, a cardiologist interviewed for NPR’s Morning Edition 2022.
Anticholinergics: Used to treat everything from Parkinson’s symptoms to chronic obstructive pulmonary disease (COPD), bladder conditions, and gastrointestinal disorders, anticholinergics block involuntary muscle movement and can reduce sweat production. A BMJ Journals case report from 2021, “Use of multiple anticholinergic medications can predispose patients to severe non-exertional hyperthermia,” detailed a patient who developed non-exertional hyperthermia from the anticholinergic effects of her medications.
Allergies: Antihistamines such as diphenhydramine and decongestants such as pseudoephedrine can also have an anticholinergic effect, decreasing blood flow to the skin and reducing sweat production, per the Mayo Clinic’s website.
Psychotropics: Antipsychotics such as risperidone and olanzapine and tricyclic antidepressants such as amitriptyline and nortriptyline can reduce the body’s ability to sweat and impair the hypothalamus’s ability to regulate temperature. Anxiolytics like benzodiazepines can also impair sweat production and reduce temperature perception. Stimulants such as amphetamines and methylphenidate used to treat ADHD can raise body temperature and decrease sweating, per the Ohio Department of Mental Health’s “Heat Related Illness in Psychotropic Medication Users.”
There is extensive data available on medication side effects. Commonly prescribed drugs such as contraceptives, acne medications, antibiotics, and supplements contain ingredients that may cause photosensitivity and can increase one’s risk of sunburn, per the U.S. Food and Drug Administration’s website. However, the limited number of studies on the relationship between medications and heat-related illness underscores the need to consider any drugs a patient is taking when evaluating their condition and advising them during the summer months.