6200 Hematopoietic Drugs Stark.docx

Hematopoietic DrugsNancy Stark RN, DNP, CNAA BC NURS: 6200 Healthcare Therapeutics Drugs to Focus On Antiplatelets, anticoagulants, thrombolytics Antiplatelets Cyclooxygenase inhibitor - Aspirin Adenosine diphosphate receptor antagonists - ticlopine (Ticlid) clopidogrel (Plavix) Glycoprotein IIbIIIa receptor antagonists ? abciximab (Reopro) Anticoagulants ? Factor V and thrombin inhibitor - Heparin (unfractionated, low molecular weight), Vitamin K antagonist - Warfarin (Coumadin) Direct Thrombin inhibitors ? Argatroban (Acova) Thrombolytics - Streptokinase (Streptase) alteplase (tPa) Steps in the Process of Hemostasis Vessel Spasm Formation of the Platelet Plug Blood Coagulation Clot Retraction Clot Lysis Thrombi Thrombus ? blood clot within a vessel or the heart Arterial ? begin with formation of a platelet plug, which is reinforced with fibrin Venous ? begin with fibrin, and enmesh RBC and platelets Arterial thrombi ? best treated with antiplatelet medications Venous thrombi ? best treated with anticoagulant medications Anticoagulants, Antiplatelets, Thrombolytics Antiplatelets ? drugs that inhibit platelet aggregation (Aspirin, ADP antagonists GPIIb/IIIa inhibitors) Anticoagulants ? drugs that depress the clotting cascade, suppress the production of fibrin (Heparin, Warfarin, Argatroban) Thrombolytics ? drugs that promote the lysis of fibrin and the dissolution of thrombi (streptokinase, alteplase) Anticoagulants General use: Prevention and treatment of thromboembolic disorders. Actions: Prevents fibrin clot formation by disrupting the coagulation cascade Contraindications: any patient with underlying coagulation disorders, recent OR or active bleeding Precautions: Any patient with potential site for bleeding. Interactions: other drugs and Warfarin Anticoagulants - ?The goal of anticoagulant therapy is to reduce blood coagulability to a level that is low enough to prevent thrombosis, but not so low as to promote spontaneous bleeding?. Heparin Given when rapid onset of anticoagulation desired Heparin (Unfractionated) Given IV or SC, no oral absorption Decreases fibrin formation ? by promoting inactivation clotting factors (XA and thrombin inhibitor), through antithrombin Plasma levels vary ? monitor PTT Hepatic metabolism, renal excretion, Half life: 1.5 hrs (normal renal, liver function) Hemorrhage/bleeding is the principal complication, also HIT Protamine sulfate ? antidote for too much heparin If bleeding is a complication of heparin therapy ? what clinical manifestations would the nurse observe for? What patient populations would heparin be contraindicated for? Your patient is admitted with a DVT. The patient is started on heparin therapy. After being on the drip for 6 hours, a PTT is drawn. The PTT result is 45. What would you anticipate being done with the heparin infusion? Low Molecular Weight Heparin Enoxaprin (Lovenox), Dalteparin (Fragmin) Given SQ Advantages; Given on a fixed dose schedule PTT monitoring not required Less likely to cause thrombocytopenia Can be used at home Adverse effects - bleeding Direct Thrombin Inhibitors Argatroban (Acova) Action: direct inhibition of thrombin IV ? 2mcg/kg/min, if liver prob. 0.5 mcg/kg/min Pharmacokinetics ? short half-life (45 min), liver metabolism Treatment alternative for patients with HIT Adverse effects: bleeding, allergic reactions (dyspnea, cough, rash) Costly Warfarin (Coumadin) Used to prevent thrombosis ? acts as an antagonist of Vitamin K, interferes with the clotting cascade PO, well absorbed Slower onset of action than heparin ? long term prophylaxis, not useful in emergencies Liver excretion, half-life 12 hrs to 3 days. Plasma levels vary ? monitor PT, INR Bleeding is the major complication Vitamin K ? used to treat overdose Many drugs/foods affect activity of warfarin. Genetic variation Monitoring Warfarin Therapy Warfarin Interactions Does the existence of a drug-drug or a drug-food interaction mean that the warfarin should not be prescribed? What effect will eating foods high in Vitamin K have on warfarin therapy? What dietary instruction should be given to a client being discharged on warfarin therapy? What foods are high in Vitamin K? Anticoagulants Which anticoagulant is used for rapid anticoagulation? Which one is slow? What lab is used to monitor heparin therapy? Coumadin therapy? Which anticoagulant is only given PO? What is the reversal agent for heparin? Coumadin? Which anticoagulant might be given when a client has HIT? Antiplatelet Drugs General use: prevention of thrombosis Actions: suppresses platelet aggregation and prolongs bleeding time. Contraindications: hypersensitivity, ulcers, active bleeding, recent surgery Precautions: any patient with a risk of bleeding. Interactions: concurrent use with NSAIDs, heparin, thrombolytic agents or warfarin may increase bleeding risk. Aspirin Adenosine Diphosphate Receptor Antagonists- Ticlopine (Ticlid) & Clopidogrel (Plavix) Glycoprotein IIb/IIIa Receptor Antagonists ? Abciximab (ReoPro), Eptifibatide (Integrelin) Tirofiban (Aggrastat) Antiplatelet Drugs - Aspirin Inhibition of cyclooxygenase -> thromboxane A can?t be synthesized ->inhibits platelet aggregation and vasoconstriction 81 to 325 mg per day. SE: bleeding problems, and anaphylaxis Adenosine Diphosphate Receptor Antagonists Inhibits platelet aggregation by antagonistic action on ADP Ticlopine (Ticlid) Indicated to prevent ischemic stroke. Can cause life threatening hematologic reactions. Clopidogrel (Plavix) secondary prevention of ischemic stroke, MI, or atherosclerotic events. Adverse events about the same as ASA. Glycoprotein IIb/IIIa Receptor Antagonists ?Super aspirins? most effective antiplatelet therapy. $$$$$ Blockage of platelet receptors to inhibit the final step in aggregation. Can block aggregation from any path. Used short-term to prevent ischemic events. May be given with heparin and ASA therapy. Bleeding is the primary adverse event. Your patient has had an acute MI and is now receiving clopidogrel and aspirin. Both are anti-platelet drugs. Why is the patient on two anti-platelet medications? Why would a client who is taking prophylactic aspirin therapy and is now scheduled for surgery be advised to stop the aspirin therapy 7-10 day prior to OR? Thrombolytic Drugs Use: acute MI, pulmonary emboli, DVT, stroke Actions: tissue plasminogen activator converts plasminogen to plasmin, which degrades fibrin in clots Adverse effects: bleeding Contraindications: hypersensitivity, active internal bleeding. Precautions: Extreme caution if other risk of bleeding. Interactions: ASA, NSAIDS, heparin, other anticoagulant or antiplatelet drugs Thrombolytic (fibrinolytic)Drugs Streptokinase (Streptase) Alteplase (tPA) Reteplase (Retavase) Urokinase (abbokinase) Anistreplase (Eminase) Streptokinase Protein extracted from streptococci cultures. Given to remove thrombi that have formed. Prototype thrombolytic drug. Indicated in acute MI, DVT, massive PE. Adverse effects Bleeding is major complication Hypotension fever Alteplase Produced by recombinant DNA technology Indicated in MI (slightly better than streptokinase), pulmonary embolus, acute ischemic stroke $$$$$ 7 to 8 x steptokinase Adverse effects: Bleeding GUSTO ? global utilization of streptokinase and tPA for occluded coronary arteries Your patient has acute coronary syndrome. The patient has a history of a stroke within the past two months. Should a thrombolytic agent be administered? What other patient populations might this class of drug be contraindicated in? What are nursing implications for a client taking a thrombolytic?