Before revision:  We conducted an 18-month study of DDI occurrence in Blumenau (Brazil ; pop. 340,000) using city-wide drug dispensing data from both primary and secondary-care level.
After revision:  We present a large-scale longitudinal study of the DDI phenomenon at the primary- and secondary-care level using electronic health records from the city of Blumenau in Southern Brazil (pop. ~ 340,000) using city-wide drug dispensing data from both primary and secondary-care level.