Infarmed warns that intense heat can compromise the safety and effectiveness of medications

Infarmed warned today that intense heat can affect the safety and effectiveness of medications, and some, such as diuretics or antidepressants, can compromise the body's thermal regulation, especially in the elderly, chronically ill, obese, children, and bedridden individuals.

To avoid this situation, the National Authority for Medicines and Health Products (Infarmed) makes available on its website the document “Medicines and heat” which answers frequently asked questions, gives “useful advice” and guidelines for maintaining the effectiveness of drugs.

Infarmed emphasizes that “exposure to high temperatures can compromise the safety and efficacy of medications,” and drugs such as diuretics, antidepressants, antihypertensives, or antipsychotics can interfere with the body's thermal regulation mechanisms.

"This situation is particularly relevant for the elderly, chronically ill, obese, children, and bedridden people, who have greater difficulty adapting to the heat," he emphasizes.

Márcia Silva, head of the Drug Risk Management Department (DGRM) at Infarmed, explains that, “in most cases, drugs do not, in themselves, represent a risk factor, especially when used correctly according to the doctor or pharmacist’s instructions.”

However, he warns, “there are numerous risk factors related to health that interfere with the body's ability to regulate temperature and consequently reduce its ability to withstand heat, which we need to be aware of.”

According to Infarmed, medicines must be stored and transported according to the instructions in the package leaflet, as heat can alter the properties of the medicines.

"Medicines that require refrigeration (between 2°C and 8°C) should be transported in refrigerated insulated bags, without being frozen. Other medications should also be protected from high temperatures," he recommends.

The drug authority advises patients, in the event of a heat wave, not to interrupt treatment without medical advice, because this decision "can lead to serious complications linked either to the sudden interruption of medication or to the effects of the untreated disease."

It also recommends that those taking medication avoid consuming alcoholic beverages, as these aggravate dehydration, and “not take any medication without the guidance of a doctor or pharmacist, even those that are not subject to a prescription.”

The Portuguese Institute of the Sea and Atmosphere (IPMA) predicts a rise in temperatures from Thursday, and especially from Friday, with maximum temperatures reaching values above the average for the time of year, “starting to contribute to a heat wave at least until the 30th”.

“A significant rise in air temperature is expected from Thursday the 24th, with maximum temperatures above 30°C across most of the mainland, and expected to reach 40°C in some places, particularly in the interior of the South region and in the Tagus valley,” it said in a statement published on the website.

According to the IPMA, the minimum temperature is expected to exceed 20°C in some inland areas, particularly in the South, Tagus Valley and Beira Baixa.