This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Pharmacology, Subject name: Pharmacology
Your medical student patient suffers from troublesome allergic rhinitis due to pollen, and you want to prescribe a drug for her that is least likely to cause sedation. Your best choice would be 
Select and explain. 
A. betamethasone, B. cimetidine, C. hydroxyzine, D. loratadine
D: loratadine
Answer: D: loratadine 
Explanation: The usual choice for pollen-induced allergies would be an H1 antagonist. Of the two listed, loratadine would be the best choice in this case because it does not cross the blood-brain barrier and is nonsedating; hydroxyzine is an effective CNS depressant used for preoperative sedation. Cromolyn (not listed) can also be used in allergic rhinitis and is also non-sedating. Betamethasone, a potent anti-inflammatory steroid, is less effective than antihistamines in this situation and would cause more serious side effects. Metoclopramide is a DA receptor antagonist and prokinetic used as an antiemetic and in GERD. Cimetidine is the prototype H2 antagonist used in GI ulcers.