Dose reduction decreased mean exposure by 29 % ( from 485 ng/mL [ SD 458 ] to 346 ng/mL [ 309 ] ) and 35 % ( from 245 ng/mL [ 227 ] to 160 ng/mL [ 145 ] ) and mean anti-FXa activity by 25 % ( from 085 IU/mL [ 076 ] to 064 IU/mL [ 054 ] ) and 20 % ( from 044 IU/mL [ 037 ] to 035 IU/mL [ 028 ] ) in the higher-dose and lower-dose regimens , respectively .