Answer to Question 1
Correct Answer: 2
Rationale 1: Substituting the liquid form for another form will not make any difference.
Rationale 2: Diphenhydramine is an antihistamine with a potent anticholinergic effect that promotes dry mouth.
Rationale 3: Diphenhydramine does not reduce fluid intake in a significant way.
Rationale 4: The client might sleep with the mouth open, but that is not the primary cause of the dry mouth.
Global Rationale: The major adverse effect of antihistamines relates to their anticholinergic effects. Excessive drying of mucous membranes can lead to dry mouth, and urinary hesitancy may be troublesome for patients, especially those with prostatic hyperplasia. Some antihistamines produce more pronounced anticholinergic effects than others. Diphenhydramine and clemastine exhibit a significant incidence of anticholinergic adverse effects, whereas the second-generation agentsloratadine, desloratadine, and fexofenadineproduce the least. Substituting the liquid form for another form will not make any difference. Diphenhydramine does not reduce fluid intake in a significant way. The client might sleep with the mouth open, but that is not the primary cause of the dry mouth.
Answer to Question 2
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.