This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which does not act by blocking NMDA receptors? 
Select and explain. 
A. Methoxetamine, B. Methadone, C. Ketamine, D. Diltiazem
D: Diltiazem
Answer: D: Diltiazem 
Explanation: Ans. is 'd' i.e., Diltiazem Drugs acting by blocking NMDA receptors are: Methoxetamine Phencyclidine Methadone Dizocilpine Felbamate Dextropropoxyphene Acamprost Tramadol Ketamine Pethidine Atomoxetine Nitrous oxide