Soltara

H1 antagonists, also called H1 blockers, are a class of medications that block the action of histamine at the H1 receptor, helping to relieve allergic reactions. Agents where the main therapeutic effect is mediated by negative modulation of histamine receptors are termed antihistamines; other agents may have antihistaminergic action but are not true antihistamines.[citation needed] In common use, the term "antihistamine" refers only to H1-antihistamines. Virtually all H1-anti... [wikipedia]