A patient was prescribed loratadine to treat allergic cheilitis. What is the mechanism of action of this drug?

Answer options

1. Increases activty of monoamine oxidase
2. Blockade of adrenergic receptors
3. Blockade of Ei-histamine receptors
4. Suppresses activity of choline esterase
5. Suppresses activity of Na+/K+-ATPase

Explanation

Loratadine is an Anti-histamine drug that blocks H1 histamine receptors. Note that most anti-histamines have the ‘-ine’ ending (Acrivastine, Clemastine, Cetirizine, Cimetidine, Famotidine)