Some medications can make people more vulnerable to heat

A study published last April by the Centers for Disease Control and Prevention of the United States of America (USA) indicated that the turnout for primary health care was substantially higher in the summer of 2023 compared to all summers in previous years. This may indicate that increasingly intense heatwaves, with increasingly extreme temperatures, may be affecting a greater number of people.

(…) more studies are still being developed to confirm the correlation [entre as ondas de calor, os medicamentos e as idas às urgências] in larger populations and more diverse groups of individuals (…)

The same study indicates that patients using antipsychotics become particularly vulnerable to certain heat-related illnesses and adverse side effects of these medicationswhen there are more than 5 consecutive days with maximum temperatures 5 ºC above the normal temperature for the season.

Patients with chronic illnesses, such as schizophrenia, diabetes, cardiovascular or even respiratory diseases, are, in themselves, more vulnerable to hot flashes.but it is now known that the medications they need can make them even more vulnerable, worsening the risk of death.

Antipsychotics are divided into conventional antipsychotics and 2nd generation antipsychotics (SGAs), based on their activity and affinity with specific neurotransmitter receptors.

The medications that are most commonly prescribed for these pathologies interfere with the body’s ability to protect itself from heat.. Diuretics, beta blockers or stimulants interfere with the human body’s ability to radiate heat, causing body temperature to rise, sometimes to levels that require hospitalization.

Direct consequences

In Portugal and the European Union, visits to health centers and hospital emergency rooms due to drug-induced hyperthermia still represent a residual percentage of total users, a situation that could change in the coming years. Our body is programmed to maintain a constant temperature, which varies between 36 ºC and 37 ºC, and a temperature above 40 ºC can, in certain cases, be fatal.

Hyperthermia is a situation that occurs when the body has a higher temperature than normal, being triggered by other factors that are not related to the fight against infectious agents, something that is characteristic of fever.

In maintaining this balance, The hypothalamus is a fundamental brain structure that controls sweat production and the need to urinate. However, it is the function of the hypothalamus that is affected by anticholinergic, antipsychotic and neuroleptic medications. These “mask” the sensation of heat, in addition to being able to cause blurred vision, fever and a change in mental state.

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One of the ways to minimize these problems is to combine medications that increase the risk of hyperthermia with others that can control some of the side effects.. Furthermore, more studies are still being developed to confirm the correlation described above, in larger populations and more diverse groups of individuals, with results expected to be available in the coming years.