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What to do when antihistamines do not work anymore?


There are two main categories of antihistamine drugs: the first generation, the oldest, with promethazine (Phenergan), dexchlorpheniramine (Polaramine or Periactin), and cyproheptadine (Periactin), and those of the second generation (Cetirizine, Loratadine). Second-generation antihistamines produce fewer side effects than those of the previous generation.

The most widely used antihistamine is cetirizine, which can be found in Actifed allergy, Alairgix or Zyrtecset. It is sometimes associated with pseudoephedrine, which will provide a decongestant effect.

These medications come in the form of tablets to be swallowed with a glass of water. They are effective in case of rhinitis, conjunctivitis or urticaria.

Is there any benefit to taking a new antihistamine?

The latest antihistamines on the market (Bilaska®, Inorial®) and prescription would cause less sleepiness than others. However, rare people still feel these effects! Depending on the case, these antihistamines also interact with certain drugs (erythromycin, ketoconazole). And, as a precaution, they are not recommended during pregnancy. Some must also be taken away from meals and without grapefruit juice, which decreases their effectiveness by 30%.

What to do when they do not “walk” anymore?

In general, if antihistamines are no longer as effective, it is because allergic rhinitis has evolved and chronic inflammation has developed. In chronic rhinitis, the nose becomes autonomously hyperactive, and antihistamines have less effect. After an allergic assessment, the doctor can then prescribe other drugs, such as corticosteroids nasal spray, or eye drops containing cromones in case of conjunctivitis. It can also offer desensitization, if it is possible, in order to gradually rehabilitate the body with the responsible allergen.

Can they dispense with desensitization?

Yes, provided that they are effective enough and enough to calm the allergic symptoms. Desensitization is only recommended in three situations: if allergic reactions persist despite well-conducted treatment; if the patient becomes asthmatic; or if it does not support local treatments.

And if we do it anyway?


Antihistamines can be taken desensitizing, but it is rarely necessary. Allergic reactions have become exceptional with sublingual desensitization, more and more used (80% of cases).

If the allergic reaction persists or intensifies, can we resume?

No. If you have an allergic reaction and the antihistamines have not worked or the symptoms are worsening, emergency procedures should be used. Call for help (by dialing 15), then take a dose of bronchodilator if breathing difficult or asthma attack (to be renewed every 5 minutes while waiting for help). An injection of epinephrine is necessary in case of appearance of general signs: malaise, difficulty breathing, intense abdominal pain, edema, hoarse cough. Followed by another in the absence of response 5 to 10 minutes after the first sting.

They prevent other allergies?

In no way, since antihistamines are only symptomatic treatments. They do not act on the evolution of allergy: eczema, food or respiratory allergy, asthma. Indeed, only desensitization seems to reduce the risk of developing new allergies and prevent the onset of asthma. This has been demonstrated in children, especially with desensitization to pollen birch and grass.

Allergies: inside too!

It is estimated that air is 5 to 10 times more polluted inside than outside. This accentuates the occurrence of many allergies. Often undiagnosed, they can get worse if they are not properly supported.

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