What can antihistamines do?

This video briefs us about antihistamines, its mode of action and signs and symptoms relation to to allergic reaction and the drugs classified as antihistamines in layman terms. TIMELINE: 0:10 Introduction 0:44 Allergic reactions 0:58 Symptoms related to histamines usage 1:34 H1 and H2b receptors 1:41 Antihistamines 1:58 H1 antihistamines and 1st , 2nd generation drugs 2:28 Examples 3:10 H2 antihistamines 3:49 Skin testing 4:39 Conclusion