1767
METHODS : In this cross - sectional study interview , ECGs and blood samples were collected in a population of adult heroin addicts treated with methadone or buprenorphine on a daily basis .
 Chemical: heroin; Chemical: methadone; Chemical: buprenorphine
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: heroin; Chemical: methadone; Chemical: buprenorphine