The nurse is teaching a client about the use of antihistamines for allergic rhinitis. Which pointer ...

Correct Answer: 4
Rationale 1: Antihistamines are most effective if taken prior to exposure to allergens. Exposure is episodic.
Rationale 2: Antihistamines work best on an empty stomach.
Rationale 3: Antihistamines cannot stop allergic reactions that are well under way.
Rationale 4: Antihistamines are most effective if taken prior to exposure to allergens.
Global Rationale: Antihistamines are most effective when taken prophylactically to prevent allergic symptoms. Their effectiveness in reversing allergic symptoms that have already manifested is limited. This is because antihistamines block the effect of histamine at its receptor sites. They do not prevent the release of histamine from mast cells. Their effectiveness may diminish with long-term use. Antihistamines work best on an empty stomach.