What is the method of action of H1-receptor antagonists?

H1 receptors, histamine induces the features of immediate-type (type 1) hypersensitivity

What is the main clinical use of H1-receptor antagonists?

• Allergies, particularly hay fever
• To aid relief of pruritus and urticaria
• Adjunctive treatment in anaphylaxis

What are the main contraindications of H1-receptor antagonists?

severe liver disease

Why do first-generation H1-receptor antagonists cause sedation?

They cross the blood brain barrier and H1 receptors, has a role in the brain in maintaining wakefulness

What is an example of a first-generation H1-receptor antagonists?

chlorphenamine

What is an example of a second-generation H1-receptor antagonists?

loratadine, cetirizine and fexofenadine