NR 566 Week 5 Study Guide {2020}– Johns Hopkins University School of Nursing (Answer &Question 98% )
NR566 Week 5 Study Outline
Chapter 18: Drugs
... [Show More] Affecting the Hematopoietic System
• Know the pharmacodynamics, pharmacotherapeutics clinical use, drug interactions and adverse drug reactions for:
Anticoagulants
• Pharmacodynamics
• Oral anticoagulants such as warfarin (Coumadin) inhibit the hepatic synthesis of several clotting factors, including factor X.
• Heparin inhibits the activity of several activated clotting factors by accelerating the activity of antithrombin III.
• LMWH enoxaparin (Lovenox) potentiates the activity of antithrombin III and inactivates factors Xa and IIa (thrombin).
• Dabigatran (Pradaxa) is a direct thrombin inhibitor.
• Thrombin is required for the conversion of fibrinogen to fibrin in the clotting cascade, thus dabigatran's inhibition of thrombin prevents thrombi from forming.
• Fondaparinux (Arixtra) is a selective inhibitor of antithrombin III and a factor Xa inhibitor.
• Rivaroxaban (Xarelto) an anticoagulant, is a highly selective factor Xa inhibitor that inhibits thrombin formation and the development of thrombi.
• Apixaban (Eliquis) is a selective inhibitor of factor Xa.
• Aspirin antagonizes the cyclooxygenase pathway and interferes with platelet aggregation.
• NSAIDs have this same action.
• NSAIDs are not used as antiplatelet drugs, but this explains why concurrent use with anticoagulants is contraindicated
• Ticlopidine (Ticlid) and clopidogrel (Plavix) reduce platelet aggregation by inhibiting the ADP pathway of platelets.
• Unlike aspirin, they have no effect on prostaglandin metabolism.
• Ticagrelor (Brilinta) reversibly interacts with the platelet P2Y12 ADP-receptor to prevent platelet activation.
• Vorapaxar (Zontivity) is a protease-activated receptor-1 (PAR-1) antagonist, inhibiting thrombin-induced and thrombin receptor agonist peptide-induced platelet aggregation
• Pharmacotherapeutics:
• Precautions and Contraindications
• All anticoagulants are contraindicated for patients who are hypersensitive to the drug or actively bleeding or who have hemophilia, thrombocytopenia, severe HTN, intracranial hemorrhage, infective endocarditis, active tuberculosis, or ulcerative lesions of the GI tract.
• Heparins are contraindicated in advanced hepatic or renal disease.
• They may be used in patients who are actively bleeding to treat DIC
• Heparin is Pregnancy Category C: stillbirth, prematurity
• Some heparin preparations contain benzyl alcohol: known to cause “gasping syndrome”:
• fatal toxicity in neonates
• Hyperkalemia may develop
• Use for patient with DM or renal insufficiency requires care and frequent monitoring of aPTT
• Has been associated with fatal medication errors r/t different strengths of preparations
• JCo: anticoagulant therapy is a National patient Safety Goal: plan in place at each facility to reduce patient harm
• LMWHs are contraindicated for patients with allergies to pork, sulfites, or benzyl alcohol; uncontrolled bleeding; and in patients who have antiplatelet antibodies
• Renal impairment: cautious use
• Body weight less than 50 kg associated with increased r/f bleeding:
• enoxaparin dose adjustment
• Cautious use: untreated HTN, retinopathy (HTN or DM caused), severe liver disease, recent Hx of ulcer, or malignancy
• Not used for thromboprophylaxis in patients with mechanical heart values: especially [Show Less]