16077
Respiratory depression and death secondary to respiratory arrest have occurred after oral overdoses of gamma - hydroxybutyrate ( GHB ) and its precursor gamma - butyrolactone ( GBL ) .
 Chemical: gamma - hydroxybutyrate; Chemical: GHB; Chemical: gamma - butyrolactone; Chemical: GBL
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: gamma - hydroxybutyrate; Chemical: GHB; Chemical: gamma - butyrolactone; Chemical: GBL