2801
A 75-year-old man developed bilateral lower leg edema 6 months after switching from troglitazone to pioglitazone.
 ( adverse event: developed ,  A 75-year-old man: Subject, 75-year-old: Subject.Age, man: Subject.Gender, bilateral lower leg edema: Effect, 6 months after switching from troglitazone to pioglitazone: Treatment, pioglitazone: Treatment.Drug, 6 months: Treatment.Drug, troglitazone: Treatment.Drug) 
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:
 ( adverse event: developed ,  A 75-year-old man: Subject, 75-year-old: Subject.Age, man: Subject.Gender, bilateral lower leg edema: Effect, 6 months after switching from troglitazone to pioglitazone: Treatment, pioglitazone: Treatment.Drug, 6 months: Treatment.Drug, troglitazone: Treatment.Drug) 