<prompt> The mechanism of action of Rivaroxaban, used in the treatment of heparin induced thrombocytopenia and thrombosis syndrome is:Direct factor Xa inhibitorActivated factor VIIaVitamin K antagonistNone of the above  <response>: Rivaroxaban is the first orally active Factor Xa inhibitor. Useful in Heparin induced thrombocytopenia and thrombosis syndrome. Ref: Harrisons principles of internal medicine, 18th edition, Page 2737 