NR 566 Week 5 Study Outline | NR566 Week 5 Course Outline

Document Content and Description Below

NR 566 Week 5 Study Outline Many questions are written to assess your clinical application of the material from the textbook, in real-world scenarios. Chapter 18: Drugs Affecting the Hematopoietic ... System • Know the pharmacodynamics, pharmacotherapeutics clinical use, drug interactions and adverse drug reactions for: • 
o Anticoagulants 
 • Pharmacodynamics Oral anticoagulants such as warfarin (Coumadin) inhibit the hepatic synthesis of several clotting factors, including factor X. The decline in clotting factors is a function of the half-life of each factor, which varies from 5 hours for factor VII to 72 hours for factor II. • 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. An anticoagulant, rivaroxaban (Xarelto), 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 • Precautions and Contraindications All anticoagulants are contraindicated for patients who are hypersensitive to the drug or actively bleeding or who have hemophilia, thrombocytopenia, severe hypertension (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 disseminated intravascular coagulation (DIC). Heparin is Pregnancy Category C. • LMWHs are contraindicated for patients with allergies to pork, sulfites, or benzyl alcohol; uncontrolled bleeding; and in patients who have antiplatelet antibodies. Use caution in hepatic dysfunction and use of warfarin and increased risk of bleeding with adults Warfarin crosses the placenta and can cause hemorrhagic disorders in the fetus and serious birth defects. It is Pregnancy Category X and should not be administered during pregnancy. Rivaroxaban (Xarelto) was given a Black-Box Warning in August 2013 indicating the premature discontinuation of anticoagulants including rivaroxaban may lead to thrombotic events. An increased risk of stroke is seen in patients with atrial fibrillation when transitioning to warfarin. Rivaroxaban is Pregnancy Category C and is not recommended for use in pregnant women. Apixaban (Eliquis) was given a similar Black Box warning regarding premature discontinuation leading to thrombotic events when it was approved. Although there are no well-controlled studies, apixaban is Pregnancy Category B. Hypersensitivity to aspirin and cross-sensitivity with NSAIDs may occur, contraindicating the drug. Aspirin hypersensitivity is more prevalent in patients with asthma, nasal polyps, or chronic urticaria. Reye syndrome has been associated with its use in children and teenagers who have influenza or chickenpox. Reversible hepatotoxicity has occurred. [Show More]

Last updated: 3 years ago

Preview 1 out of 8 pages