Between Nov 26 , 2009 , and Nov 20 , 2012 , 508 patients were randomly assigned to receive benzathine benzylpenicillin ( n = 165 [ 156 analysed ] ) , twice-daily co-trimoxazole for 3 days ( n = 175 [ 173 analysed ] ) , or once-daily co-trimoxazole for 5 days ( n = 168 [ 161 analysed ] ) .