Question

The mode of action of antihistamine is

• A. Blocking the action of histamine in circulation.
• B. Competing with the histamine for H1 receptors.
• C. Preventing the release of histamine.
• D. All of the above.

Answer 1

The correct option is D All of the above.

Histamines are the inflammatory substances which are released by the mast cells and basophils during the allergic reactions. The antihistamines are molecules which are similar in structure to histamine and block the release and action of histamines. Being structurally same, they bind to the H1 receptors which are specific for histamine. Since the receptors are blocked, the release of histamine is prevented.

Thus, the correct answer is option D.