This Tuesday, July 19, under the white neon lights of Anne-Lise’s pharmacy, in the 19th arrondissement of Paris, a small air conditioner painfully blows a little cold air into the legs of customers. Perhaps to really realize it, they approached the small white device, as if to beg for a little freshness, while outside, in the middle of a heat wave, the sun beats down on the asphalt and the thermometers do not go down not below 37°C.
In the small paper bags that customers take with them, often common medicines, such as aspirin, paracetamol, enough to refill a first aid kit before taking the road for vacation. “People come to fill up before leaving!she smiles. They buy bandages, Doliprane, aspirin, Biafine, sun creams…” Current specialties, a priori banal and without danger, which would however deserve a little attention at the time of the hot weather. Because the latter alter them and make them ineffective, or even make them downright dangerous.
Under high heat conditions, liquid medications and creams can indeed lose their stability while the suspension or emulsion can separate. Furthermore, if exposed to high heat, capsules, powders and tablets can also degrade. “Tablets and oral solutions are theoretically able to withstand short exposure to high heat, thus indicates a hospital pharmacist, whom franceinfo met. But they’re not supposed to be exposed to the heat of a car parked in the sun on an afternoon at all.”
“Before obtaining their marketing authorization, pharmaceutical companies had to carry out drug stability studies for temperatures of 30°C to 40°C degrees. But rarely beyond.”
A hospital pharmacistat franceinfo
With, in addition, a real uncertainty about their effectiveness in these conditions. It is possibly acceptable for the aspirin of the small headaches, less when the survival of the patient depends on his treatment…
Not to mention that some medications aggravate the heat effect. “To adapt to the heat, we sweat, but in doing so, we dehydrate,” explains the pharmacist. By causing a strong elimination of urine and significant sweating, certain drugs such as diuretics can cause dehydration.
This is the case, for example, of ACE inhibitors, or drugs used in psychiatry, such as neuroleptics, which can cause a rise in temperature. Or so-called “narrow therapeutic walk” drugs, that is to say those whose dosage is very controlled so that they are effective and do not cause adverse effects.
“With the heat, continues the practitioner, significant dehydration will lead to an increase in the concentration of these drugs and cause adverse effects in the patient. Like lithium salts which become toxic in the event of dehydration, or certain antibiotics or antivirals which, in the absence of sufficient hydration, can cause kidney dysfunction and accelerate the process of dehydration.
Among the ailments of summer, sunburn, sunstroke. And among its tragedies, heat stroke, which can be fatal. It occurs when the body can no longer control its temperature. The latter increases, causing high fevers and loss of consciousness. The victim vomits, is nauseous, suffers from headaches, delirium, even convulses. This is a serious emergency, which must be treated quickly: call the emergency services. Forget aspirin and paracetamol, recommends the National Medicines Safety Agency (ANSM): paracetamol is ineffective in cases of heat stroke, and aspirin can disrupt the body’s thermoregulation.
Moreover, who says heat, often says… sun. And this one is also a bad comrade for certain drugs that contain a photosensitizing specialty.
“The risk of photosensitization is real for certain drugs, which then cause, when the subject is exposed to the sun, allergies or spots on the skin, which can be irreversible.”
A hospital pharmacistat franceinfo
This risk is indicated on the medicine leaflet by a small red triangle pictogram containing a sun and a small cloud. “Under the effect of the sun, continues the pharmacist, these medications can cause, in the minutes or hours following exposure, burns, sunburn, with or without bubbles, sometimes localized at the level of the area of application of the medication if it is a cream or ointment, or on parts exposed to the sun if the drug was taken systemically, as is the case for example for an antibiotic.
Among them (this – long – list is not exhaustive), taken orally: nonsteroidal anti-inflammatories, antiepileptics, diuretics (sulfonamide, triamterene), oral antidiabetics, in particular hypoglycaemic sulfonamides such as glimepiride or glibenclamide. Or isottretinoin, used to treat acne, antibiotics such as Ciflox, Tavanic, Oflocet, as well as drugs used in neuropsychiatry (Tofranil, Tegretol…). Among the photosensitizing drugs applied locally (in cream therefore, often), one will find for example ketoprofen (for example Ketum), or even antiallergic or anti-acne ointments.
Finally, the ANSM reminds us, in all cases, you should never stop your treatment without first consulting a doctor or pharmacist, at the risk of exposing yourself to complications, linked either to the sudden discontinuation of the drug, or related to the disease itself, since it is no longer treated.