2806
There was mutual potentiation between sub - effective doses of ketamine and morphine , but sub - effective doses of ketamine partly antagonized fully - effective doses of morphine .
 Chemical: ketamine; Chemical: morphine; Chemical: ketamine; Chemical: morphine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: ketamine; Chemical: morphine; Chemical: ketamine; Chemical: morphine