A student needs to take an antihistamine for chronic rhinitis. Which preparation is least likely to ...

Correct Answer: 4
Rationale 1: Hydroxyzine (Atarax) is a sedating first-generation antihistamine.
Rationale 2: Cetirizine (Zyrtec) is more sedating than other second-generation agents.
Rationale 3: Diphenhydramine (Benadryl) is a sedating first-generation antihistamine.
Rationale 4: Fexofenadine (Allegra) is the least sedating of the second-generation antihistamines.
Global Rationale: First generation antihistamines like hydroxyzine and diphenhydramine have sedation as a significant adverse effect. This effect is lessened in the second generation antihistamines such as cetirizine and fexofenadine. Cetirizine appears to be somewhat more sedating than other second-generation agents.

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