List and sedating antihistamines Adult chat messengers
Antihistamines have no role in the acute management of anaphylaxis.
Antihistamines are used in the management of allergic conditions.
They have been taken by a large number of pregnant women and women of childbearing age without any proven increase in malformations or harm to the fetus.
An exception is promethazine for which adverse events have been reported in animal studies (at very high doses).
Topical nasal antihistamines, such as azelastine, are also available and are recommended for nasal-limited mild disease and for on-demand treatment.
To augment the efficacy of oral antihistamines in allergic rhinitis for those who continue to have symptoms, the preferred topical therapy is a corticosteroid nasal spray.
Studies have shown poorer school performance in children with allergic rhinitis treated with sedating antihistamines, compared to children treated with non-sedating antihistamines and healthy children.
This led to a black box warning by the US Food and Drug Administration (FDA) in 2004.
Sedating antihistamines are still favoured by some, as parenteral formulations are available.
Desloratadine and fexofenadine are registered for use in infants six months and older, while loratadine and cetirizine can be used from 12 months of age.
Some antihistamines are used for their antinausea or sedative Loratadine is metabolised in the liver, while cetirizine, desloratadine and fexofenadine are not metabolised extensively.
These sprays should be considered first-line treatment in moderate to severe allergic rhinitis.
Combination treatments containing both corticosteroids and antihistamines are also available.
Cetirizine is eliminated in the urine, while fexofenadine is excreted in the faeces.