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A total of 40 healthy volunteers were planned to start with 600 mg rifampicin once daily from days 1-5.
 ( potential therapeutic event: start ,  40 healthy volunteers: Subject, 40: Subject.Population, 600 mg rifampicin once daily from days 1-5: Treatment, 600 mg: Treatment.Dosage, rifampicin: Treatment.Drug, once daily: Treatment.Freq) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: adverse event,potential therapeutic event, Arguments type: Treatment.Disorder,Treatment.Time_elapsed,Treatment.Dosage,Subject.Race,Treatment.Drug,Treatment.Route,Subject.Disorder,Treatment.Freq,Treatment,Effect,Subject.Population,Treatment.Duration,Combination.Drug,Subject,Subject.Age,Subject.Gender. 
Text: {0} 
Answer:
 ( potential therapeutic event: start ,  40 healthy volunteers: Subject, 40: Subject.Population, 600 mg rifampicin once daily from days 1-5: Treatment, 600 mg: Treatment.Dosage, rifampicin: Treatment.Drug, once daily: Treatment.Freq) 