Gouvernement Princier de Monaco
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News of theme "Social Affairs and Health"
26 June 2019 Press release

You and your medication during a heatwave

© - DR

1. What are the risks associated with hot weather?

Exposure to extreme heat is harmful to the human body. The most severe complications include dehydration, heatstroke or causing an existing condition to deteriorate.

2. What happens to our bodies in hot weather?

When it’s hot, our bodies do everything they can to adapt and reduce our body temperature. The main way in which the body cools down is through the evaporation of sweat, but when it is particularly humid outside, or when there is no wind, sweat evaporates more slowly, hindering the cooling process.

If your body temperature is too high, this can have severe implications for your health.

High levels of sweating can cause your body to lose a lot of water and salt, resulting in dehydration if the water lost is not replaced through sufficient hydration (drinking fluids).

3. What is heatstroke?

Heatstroke can occur when the body is no longer able to control its temperature, which then rises rapidly. It can take hold very quickly in infants and the elderly during periods of extremely hot weather, and can also affect athletes who may not do enough to compensate for water lost through perspiration.

Heatstroke must be treated promptly in order to prevent neurological damage.

Those affected by heatstroke experience a high fever and loss of consciousness. They are also prone to vomiting, nausea, headaches, confusion and even fits. Their skin will be hot, red and dry (people suffering from heatstroke do not sweat). 

4. Why might medication pose a risk during hot weather?

Some medicines (diuretics) increase the amount of water expelled from the body through the kidneys and can therefore heighten the risk of dehydration associated with high temperatures. Dehydration can also affect the way in which some medicines are processed within the body.

Other medicines can stop the body’s normal cooling mechanisms from functioning properly. In order for the body to cool itself down, it is vital that the central nervous system is able to control dilation of blood vessels near the skin’s surface to facilitate improved blood circulation, heat removal and perspiration.

Finally, some medicines can exacerbate the effects of heat, by reducing blood pressure or by affecting alertness.

5. Which types of medication can pose a risk during hot weather?

Some types of medication can increase the risks associated with spending too long in hot conditions or with exposure to extreme heat. Extra vigilance is therefore required. These types of medication include:

• Medicines used to treat cardiac conditions: diuretics can make dehydration worse. Similarly, blood pressure and angina medication can exacerbate hypotension. All medicines used to treat heart rhythm disorders, as well as digoxin, can become toxic in the event of dehydration.

• Medicines used in psychiatric treatment: antipsychotics can interfere with the body’s central thermostat, causing your temperature to increase. Lithium salts can become toxic in the event of dehydration, and antidepressants can hinder perspiration.

• Epilepsy medication can become toxic in the event of dehydration.

• Medicines used to treat migraines can prevent dilation of blood vessels in the skin or reduce perspiration.

• Some antibiotics and some antivirals can hinder normal kidney function in the event of dehydration.

• Some immunosuppressants can hinder normal kidney function in the event of dehydration.

• Anti-inflammatories, including aspirin in doses higher than 500 mg/day, can affect kidney function in the event of dehydration.

• Some medicines used to treat Parkinson’s disease, urinary incontinence or allergies can hinder perspiration. 


In the majority of cases, medicines do not present a risk in and of themselves, particularly if they are being taken correctly. Other risk factors, including illness or advanced age, must be taken into consideration.

Always consult your doctor or pharmacist before you stop taking your medication.

6. Is medication the only risk factor?

There are numerous factors that can increase health risks during a heatwave. The elderly and children aged 0–4 years are most at risk, as well as those suffering from a fever, obesity, one or more chronic diseases, especially cardiac, renal or respiratory disorders, diabetes, neurological or psychiatric disorders and reduced independence.

7. What should you do to prepare for periods of very hot weather?

The following steps are advised, particularly if you are elderly, sick or taking medication:

• Follow normal hygiene and dietary advice. In particular, make sure that you drink regularly, protect yourself from the sun and the heat, and use appropriate methods to cool yourself down (take a shower or a bath, apply damp towels to your skin, etc.).

• Do not take medication without medical advice, even medicines sold over the counter.

• Talk to your doctor if your health condition requires regular monitoring, especially if it has been several months since your last consultation. Your doctor will carry out a full examination and make changes to your treatment if required.

In general:

• Read the leaflet enclosed with your medication carefully (make sure that you keep the leaflet together with your medicine).

• Stick to the dosage and times indicated by your doctor and pharmacist.

• Seek advice from your doctor or pharmacist if you have any questions at all, particularly if you do not fully understand the guidance leaflet included with your medicine or what your medicine is for, or if you experience any unusual symptoms.

• Tell your doctor or pharmacist about all the medicines you take regularly or occasionally, whether they are prescription or over-the-counter medicines.

8. What should you avoid when a heatwave is declared?

Never stop taking your medication without first talking to your doctor or pharmacist. This could lead to complications resulting from the abrupt withdrawal of medication or due to your condition no longer being treated.

Additionally, drinking alcohol is not recommended during periods of very hot weather, since alcohol increases the risk of dehydration. You are also advised not to take aspirin or paracetamol if you experience any unusual pain or fever. Aspirin can hinder your body’s efforts to adapt to the heat, and paracetamol is ineffective in treating heatstroke.

In all cases, seek advice from your doctor or pharmacist about any medication you are taking, even those sold over the counter.

9. How should you store your medication during very hot weather?

Normally, there will be no storage instructions indicated on the packaging of your medicines. This means that the medicine is stable, even during prolonged exposure to high temperatures. No special precautions need to be taken in these cases.

Where specific warnings relating to storage do appear on the packaging of your medicines, the following recommendations apply:

• Medicines which need to be kept at a temperature of below 25°C or 30°C can be kept in their usual place. Studies have shown that higher temperatures (such as those experienced during a heatwave) for a few days do not harm these medicines.

• Medicines which are supposed to be kept at a temperature of between +2 and +8°C are kept in your refrigerator as a matter of course and so a heatwave will not affect their stability. Once they are removed from the refrigerator, however, you should use them relatively quickly, in accordance with the dose prescribed by your doctor, and avoid leaving them out for too long. You should also avoid taking them out of the refrigerator and then returning them if they have not been used: this kind of switching between hot and cold environments is not advisable for such fragile products. In any event, you should avoid exposing your medicines to sunlight.

• Specific cases: for some types of pharmaceutical products that are sensitive to heat (suppositories, pessaries, creams, etc.), it should be relatively easy to judge from appearance on opening the product whether its quality has been maintained following exposure to heat. You should not use any product which looks visibly different: changes to the external appearance could indicate that the properties of its pharmaceutical form have been modified (regardless of the quality of the active substance).

10. How should you transport your medication during very hot weather?

• With the exception of medication that is normally stored in the refrigerator, we recommend that all medicines are transported in a non-refrigerated insulated container.

• We recommend that medicines normally kept in the refrigerator are transported in a refrigerated insulated container (for example, one which has ice packs). In doing so, you should ensure that the medicines do not freeze.

Even when kept in an insulated container, it is important to make sure that your medicines are not exposed for too long to the high temperatures often experienced in the boots or interiors of cars left in full sunlight.

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