Which medications in the drug class Antihistamines, Second Generation are used in the treatment of Chronic Urticaria?

Updated: Jul 31, 2018
  • Author: Marla N Diakow, MD; Chief Editor: William D James, MD  more...
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Antihistamines, Second Generation

Second-generation antihistamines, also known as less-sedating or low-sedation antihistamines, produce less sedation than traditional H1 blockers because they are less lipid-soluble and only cross the blood-brain barrier in small amounts. They also have longer half-lives, allowing less frequent dosing.

Cetirizine (Zyrtec)

Cetirizine forms a complex with histamine for H1-receptor sites in blood vessels, the gastrointestinal (GI) tract, and the respiratory tract. It is available as a 5- or 10-mg tablet and as a syrup containing 1 mg/mL (5 mg/5 mL [tsp]).

Fexofenadine (Allegra)

Fexofenadine competes with histamine for H1 receptors in the GI tract, blood vessels, and the respiratory tract, reducing hypersensitivity reactions. It does not sedate. Fexofenadine is available as a 30-, 60-, or 180-mg tablet. The Allegra ODT tablet is formulated for disintegration in the mouth immediately after administration. Each orally disintegrating tablet contains 30 mg of fexofenadine hydrochloride. The Allegra oral suspension contains 6 mg/mL of fexofenadine hydrochloride (30 mg/5 mL).

Loratadine (Claritin, Alavert)

Loratadine selectively inhibits peripheral histamine H1 receptors. It is available in 10-mg tablets or 10-mg RediTabs; the syrup is 5 mg/5 mL (tsp).

Desloratadine (Clarinex)

Desloratadine is a long-acting tricyclic histamine antagonist that is selective for H1 receptors. It relieves nasal congestion and alleviates the systemic effects of seasonal allergy. Desloratadine is a major metabolite of loratadine, which, after ingestion, is extensively metabolized to the active metabolite 3-hydroxydesloratadine. The tablet is 5 mg; the syrup is 0.5 mg/mL (2.5 mg/5 mL [tsp]); and the RediTabs (orally disintegrating desloratadine tablets) are 2.5 mg and 5 mg.

Levocetirizine (Xyzal)

Levocetirizine is an H1-receptor antagonist, an active enantiomer of cetirizine. It is a second-generation prescription antihistamine.

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