Antihistamines, Second-Generation
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Overview
Second-generation antihistamines selectively block peripheral H1 histamine receptors with minimal CNS penetration, producing less sedation than first-generation agents. They are used for allergic rhinitis, urticaria, and other allergic conditions.
How do antihistamines, second-generation work?
Second-generation antihistamines competitively and selectively antagonize histamine at peripheral H1 receptors, reducing vasodilation, increased vascular permeability, bronchoconstriction, and pruritus triggered by histamine release. Their poor CNS penetration results in a lower sedation profile compared to first-generation antihistamines.
Drugs in this class
- Cetirizine (Zyrtec)