Question

Which drug acts by blocking the action of histamine in circulation?

Options

• Antihistamines

• Antibiotics

• Steroids

• Adrenaline

Answer 1

Antihistamines act by blocking the action of histamine in circulation. These drugs compete with histamine for H1 and H2 receptors, preventing histamine from binding and producing its effects. By occupying the receptor sites, antihistamines reduce allergic manifestations such as itching, sneezing, and rhinitis. They are most effective when taken before or immediately after allergen exposure, and different antihistamines have varying potencies and side effect profiles.