H1 antagonist has all the function except

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. H1-antihistamines are clinically used in the treatment of histamine-mediated allergic conditions. These indications may include: Allergic rhinitis Allergic conjunctivitis Allergic dermatological conditions (contact dermatitis) Rhinorrhea (Runny nose) Uicaria Angioedema Diarrhea Pruritus (atopic dermatitis, insect bites) Anaphylactic or anaphylactoid reactions--adjunct only Nausea and vomiting Sedation (first-generation H1-antihistamines) Refer kDT 6/e 160