Which medications in the drug class Antihistamines, oral are used in the treatment of Mold Allergy?

Updated: Sep 18, 2017
  • Author: Shih-Wen Huang, MD; Chief Editor: Harumi Jyonouchi, MD  more...
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Answer

Antihistamines, oral

These agents compete with histamine to bind to H1 receptors on the endothelium and smooth muscle. Histamine is a central vasoactive mediator in allergic rhinitis, and prophylactic use of antihistamines typically provides substantial control of symptoms. Dosage of traditional (first-generation) antihistamine classes is limited by the appearance of undesirable adverse effects including sedation, restlessness, dry mouth, urinary retention, constipation, and blurred vision. For this reason, new-generation antihistamines that are mostly free of such adverse effects are welcome options for treatment. Many first-generation antihistamines are available without a prescription, and loratadine, a second-generation antihistamine, is currently available over-the-counter (OTC).

Loratadine (Claritin)

Loratadine is a nonsedating second-generation antihistamine. It has fewer adverse effects than first-generation medications. It selectively inhibits peripheral histamine H1 receptors.

Desloratadine (Clarinex)

Desloratadine relieves nasal congestion and the systemic effects of seasonal allergies. It is a long-acting tricyclic histamine antagonist selective for the H1-receptor. It is a major metabolite of loratadine, which, after ingestion, is extensively metabolized to the active metabolite 3-hydroxydesloratadine.

Cetirizine (Zyrtec)

Cetirizine selectively inhibits histamine H1 receptor sites in blood vessels, the GI tract, and the respiratory tract, which, in turn, inhibits the physiologic effects that histamine normally induces at H1 receptor sites. Once-daily dosing is convenient. Bedtime dosing may be useful if sedation is a problem.

Levocetirizine (Xyzal)

Levocetirizine is a histamine1-receptor antagonist. It is an active enantiomer of cetirizine. Peak plasma levels are reached within 1 hour and the half-life is about 8 hour. It is available as a 5-mg breakable (scored) tablet and a 0.5-mg/mL oral solution. It is indicated for seasonal and perennial allergic rhinitis.

Fexofenadine (Allegra)

Fexofenadine is a nonsedating second-generation medication with fewer adverse effects than first-generation medications. It competes with histamine for H1 receptors in the GI tract, blood vessels, and the respiratory tract, reducing hypersensitivity reactions. It does not sedate, and it is available in daily or twice-daily preparations.


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