This video tells us about allergy-related drugs histamines and antihistamines, their structure, mode of action, classification, types of drug-receptor interaction, therapeutic uses, and pharmacological action. TIMELINE: 0:17 Introduction 0:43 Histamine receptors 0:56 Mechanism of action of histamine 1:16 Releasing agents 1:33 Histamine pharmacological action 1:46 Histamine triple response 2:38 Actions of histamine 2:58 Histamines H1 receptor antagonist 3:04 Classification 3:12 Antihistamines pharmacological action 3:39 Pharmacokinetics 3:50 DRs-H1 antagonist 4:06 Therapeutic uses 5:19 H2 receptors antagonist 5:39 H3,H4 receptor antagonist 5:47 Conclusion