Antihistamines, Second Generation

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.