1271
Drug metabolism was assessed using midazolam , tolbutamide , caffeine , omeprazole , dextromethorphan , acetaminophen and repaglinide as probes .
 midazolam, tolbutamide, caffeine, omeprazole, dextromethorphan, acetaminophen, repaglinide
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 midazolam, tolbutamide, caffeine, omeprazole, dextromethorphan, acetaminophen, repaglinide