3074
Ketamine ( KET ) is the only NMDA antagonist licensed as an injectable drug in different countries and remains an anesthetic of choice in some difficult field conditions .
 Ketamine, KET, NMDA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Ketamine, KET, NMDA