This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Which of the following drug is alpha 2 agonist? 
Select and explain. 
A. Apraclonidine, B. Timolol, C. PG analogues, D. PG analogues
A: Apraclonidine
Answer: A: Apraclonidine 
Explanation: Apraclonidine - Selective alpha 2 agonist. Useful in glaucoma. Alpha agonists (Brimonidine and apraclonidine) are contraindicated in hypeensive crisis. Dipivefrin is a prodrug which is conveed into epinephrine inside ttre eyeUall, so can safely be used in hypeension. REF : katzung pharmacology : 14th ed