Answer:
An antihistamine suppresses and blocks the histamine to the receptor site preventing the histamine from binding by having a similar shape and binding characteristics.
Step-by-step explanation:
Antihistamine drugs work by blocking H1 receptors. This block prevents most histamine binding. By doing that, there is a dramatic reduction of Histamine action: reducing itching, watery eyes, urticaria, etc. Antihistamine drugs have been prescribed as an anti-allergenic class of medicine.