The Figure shows the pharmacologic profile versus time for escalating doses of rivaroxaban in a randomized, single-blind, placebo controlled study.[114] The black line in the Figure is the placebo, and it lies just along the line of 0 inhibition of factor Xa.  At its lowest dose, 5 mg (orange line), rivaroxaban’s inhibition of factor Xa falls to approximately the same as placebo by 12 hours; however, at the higher doses of rivaroxaban the factor Xa inhibition is still in the effective range out to 24 hours, and therefore the second-highest dose, 20 mg, was chosen for assessment in the pivotal Phase 3 trial of rivaroxaban, ROCKET AF. 

 Reiffel JA. Am J Med 2013; 126: 00-00.