In this case, the full medical history of the patient is not endorsed. A patient undergoing treatment of benign prostatic hyperplasia with tamsulosin, an alpha receptor antagonist, will not usually present with deranged clotting mechanisms. From the choices, only warfarin; which actions to antagonize the action of vitamin K thereby significantly reduce vitamin K dependent clotting factors such as factor II, factor VII, factor IX, and factor X. In reducing the levels of vitamin K dependent clotting factors, clotting time; both intrinsic (prothrombin time) and extrinsic (activated thromboplastin time) pathways will be deranged.