Heat wave raises risk of illness for people on certain medications
Health officials warn that common prescription and over-the-counter drugs can impair the body’s ability to cope with high temperatures, increasing the chance of dehydration and heat-related illness.
A heat wave can exacerbate the side effects of several widely used medications, making dehydration, dizziness, fainting and heat illness more likely. Health experts advise patients not to stop any drug without consulting a doctor or pharmacist, and to ask about a “hot day plan.”
The body normally dissipates excess heat by sweating, redirecting blood flow to the skin, and adjusting heart rate and blood pressure. Certain drug classes interfere with these mechanisms. Diuretics such as furosemide increase urine output and can cause electrolyte imbalances, raising the risk of falls. Beta-blockers, ACE inhibitors and ARBs may blunt heart-rate responses, lower blood pressure and reduce thirst, especially when combined with diuretics.
Mental-health medications also affect temperature regulation. Antipsychotics can hinder sweating, while some SSRIs increase it, and tricyclic antidepressants may suppress it. Stimulants prescribed for ADHD raise metabolic activity, potentially leading to overheating during outdoor activity.
Over-the-counter antihistamines, particularly older formulations like diphenhydramine, can reduce sweating and cause drowsiness, making early signs of heat illness harder to detect. People with diabetes face additional challenges; dehydration and heavy sweating can destabilize blood-glucose levels, and some diabetes drugs, such as SGLT2 inhibitors, may worsen fluid loss. Extreme heat can also impair glucose-monitoring devices and reduce insulin potency.
Patients are urged to monitor for warning signs such as dizziness, intense thirst, reduced urination, nausea, fatigue, confusion, fainting, severe headache or hot, dry skin, and to seek emergency care if severe symptoms appear.
