Agents Affecting Blood Clotting Chapter 19 Agents Affecting Blood Clotting

Anticoagulants Inhibit the action or formation of one or more clotting factors Heparin-potent inhibitor of the clotting process Used in the prophylaxis and treatment of clotting disorders

Anticoagulants Heparin Indirectly interferes with the conversion of prothrombin to thrombin The deficiency of thrombin prevents the conversion of fibrinogen to fibrin Inhibits the formation of clots

Anticoagulants Heparin Given subcutaneously of intravenously (continuous infusion) Rapid and predictable action First drug used in anticoagulant therapy Patient changed to an oral anticoagulant when a desired prothrombin time is achieved

Anticoagulants Adverse effects subcutaneous bleeding blood in the stool, hematuria bleeding gums nosebleeds bruising hypersensitivity

Anticoagulants Treatment of overdose 1% protamine sulfate Inactivates heparin Slow infusion

Anticoagulants Many drug-drug and drug-herb interactions to heparin that increase bleeding and delay clotting time Many drug-drug and drug-herb interactions that decrease the effect of heparin

Anticoagulants Lovenox Low molecular weight heparin anticoagulant Only given subcutaneously Prophylaxis and treatment of DVT

Anticoagulants Adverse effects bleeding gums nose bleeds bruising hematuria blood in stool

Oral Anticoagulants Inhibits blood clotting by interfering with the synthesis of vitamin K-dependent clotting factors in the liver Action is not evident for 12-24 hours after the first dose

Oral Anticoagulants warfarin (Coumadin) More predictable action lower incidence of adverse effects Close monitoring of the patient Dosages are individualized and dependant on INR

Oral Anticoagulants warfarin (Coumadin) therapeutic INR 2-3 Many drug-drug and drug-herb interactions Overdosage: Vitamin K

Antiplatelet Agents clopidogrel (Plavix) Inhibit the aggregation of platelets Patients following a CVA or MI May help prevent recurrence

Antiplatelet Agents Patients should avoid using medications that contain aspirin Avoid using non-steroidal anti-inflammatory drugs

Antiplatelet Agents clopidogrel (Plavix) Adverse effects dizziness nose bleeds GI bleeding bleeding

Thrombolytic Agents Enzyme that dissolves fibrin clots Indicated for the lysis of pulmonary emboli and for clearing clots from central venous catheters streptokinase urokinase

Thrombolytic Agents urokinase Drug of choice for clearing central venous catheters Patients should be monitored for bleeding