Histamine H1 Antagonists, Non-Sedating

**Definition:** A class of non-sedating drugs that bind to but do not activate histamine receptors (DRUG INVERSE AGONISM), thereby blocking the actions of histamine or histamine agonists. These antihistamines represent a heterogenous group of compounds with differing chemical structures, adverse effects, distribution, and metabolism. Compared to the early (first generation) antihistamines, these non-sedating antihistamines have greater receptor specificity, lower penetration of BLOOD-BRAIN BARRIER, and are less likely to cause drowsiness or psychomotor impairment.

**Tree numbers:** - D27.505.519.625.375.425.400.500 - D27.505.696.577.375.425.400.500

**Synonyms:** - Second Generation H1 Antagonist - H1 Antihistamines, Non-Sedating - Second Generation Antihistamines - Second Generation H1 Antagonists - Second Generation Antihistamine