Question

a nurse is teaching a client about the use of antihistamines to treat allergic rhinitis. the nurse should explain that these medications are effective because they perform which of the following actions?
decrease viscosity of nasal secretions
block $\ce{h_2}$ receptors
prevent histamine from binding to receptors
reduce nasal congestion

Explanation:

Antihistamines for allergic rhinitis work by blocking histamine, a chemical released during allergic reactions, from attaching to its target receptors, which stops the allergic symptoms. Decreasing nasal secretion viscosity and reducing nasal congestion are not their primary actions; decongestants address congestion. Blocking H₂ receptors is the action of H₂ antagonists, used for gastrointestinal issues, not allergic rhinitis.

Answer:

C. Prevent histamine from binding to receptors