2750
Whereas muscular rigidity is a well - known side effect that is associated with high - dose fentanyl anesthesia , a paucity of information exists with regard to its underlying mechanism ( s ) .
 Disease: muscular rigidity; Chemical: fentanyl
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:
 Disease: muscular rigidity; Chemical: fentanyl