This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Which of the following does not cross a blood brain barrier 
Select and explain. 
A. Pralidoxime, B. Obidoxime, C. Diacetylmonoxime, D. Physostigmine
A: Pralidoxime
Answer: A: Pralidoxime 
Explanation: Ref-Katzung 11/e p121 Pralidoxime or 2-PAM, usually as the chloride or iodide salts, belongs to a family of compounds called oximes that bind to organophosphate-inactivated acetylcholinesterase. It is used to treat organophosphate poisoning in conjunction with atropine and diazepam