Antihistamines

Question 1

Diphenhydramine, dimenhydrinate, chlorpheniramine, chlorcyclizine, hydroxyzine, meclizine, promethazine

Answer 1

First-generation antihistamines

Non-selective, potent muscarinic antagonists. Also block alpha-adrenergic receptors and/or 5-HT receptors

Treat allergies and motion sickness, and used as sleep aid.

Question 2

Cetirizine, Loratadine, fexofenadine, desloratadine

Answer 2

Second-generation antihistamines

Selective for peripheral H1 receptors (do not cross BBB). Fewer side effects (non-sedating)

Treat allergies