Drugs Acting on the Hematopoietic System

Warfarin inhibits the synthesis of vitamin K–dependent clotting factors X, IX, VII, and II. This is absorbed easily orally, but is also involved in many drug interactions. This remains the drug of choice for treatment of deep vein thrombosis (DVT) and pulmonary embolus (PE).

Heparin binds with antithrombin II and inactivates factors IXA, XA, XIIA, and XIII. Heparin is given either intravenously or subcutaneously and is extensively protein bound. Heparin also has drug interactions but not as many as warfarin.

Low-molecular-weight heparin causes the processing of heparin into smaller molecules and inactivates factor XA.

Rivaroxaban is an oral medication that acts as a factor XA inhibitor

Aspirin inhibits cyclooxygenase (COX) interferes with platelet aggregation. Generally, aspirin is well absorbed.Ticlodipine and clopidrogrel reduce platelet aggregation by inhibiting adenosine diphosphate (ADP) pathways. These drugs should be avoided in patients with liver dysfunction.