Anticoagulants and Thrombolytic Agents > Pharmacology
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Total Questions : 5
Showing 5 questions, Sign in for moreA nurse is caring for a client who has a history of coronary thrombosis and is taking warfarin as a long-term anticoagulant therapy. What laboratory test should the nurse monitor to evaluate the effectiveness of warfarin?
Explanation
The INR is a standardized measure of the prothrombin time (PT), which reflects the activity of the extrinsic and common pathways of coagulation.
Warfarin is an anticoagulant that inhibits the synthesis of vitamin K-dependent clotting factors (II, VII, IX, and X), which are involved in these pathways.
Therefore, the INR is used to monitor the effectiveness of warfarin therapy and adjust the dose accordingly.The target INR range depends on the indication for warfarin, but it is usually between 2 and 3.
Choice A is wrong because activated partial thromboplastin time (aPTT) reflects the activity of the intrinsic and common pathways of coagulation.
Heparin is an anticoagulant that enhances the activity of antithrombin, which inhibits factors II, IX, X, XI, and XII, which are involved in these pathways.Therefore, the aPTT is used to monitor the effectiveness of heparin therapy.
Choice C is wrong because platelet count measures the number of platelets in the blood, which are involved in primary hemostasis.Platelet count is not affected by warfarin therapy, but it can be decreased by heparin-induced thrombocytopenia (HIT), a rare but serious complication of heparin therapy.
Choice D is wrong because fibrinogen level measures the amount of fibrinogen in the blood, which is a precursor of fibrin, the main component of blood clots.Fibrinogen level is not affected by warfarin therapy, but it can be decreased by disseminated intravascular coagulation (DIC), a condition where widespread clotting and bleeding occur simultaneously.
The normal ranges for these tests are as follows:
• INR: 0.8 to 1.2
• aPTT: 25 to 35 seconds
• Platelet count: 150 to 450 x 10^9/L
• Fibrinogen level: 2 to 4 g/L
A nurse is teaching a client who is prescribed clopidogrel, an antiplatelet drug, to prevent recurrent stroke. Which of the following statements should the nurse include in the teaching? (Select all that apply.)
Explanation
Clopidogrel is an antiplatelet drug that inhibits the ability of platelets to clump together as part of a blood clot.It is used to prevent recurrent stroke and other cardiovascular events in people who are at high risk.
Choice A is correct because taking aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) while on clopidogrel can increase the risk of bleeding.These drugs also affect platelet function and can interfere with the action of clopidogrel.
Choice B is correct because bleeding is the most common side effect of clopidogrel.Any signs of bleeding, such as nosebleeds, bruising, or black stools, should be reported to the provider as they may indicate a serious complication.
Choice C is wrong because clopidogrel can be taken with or without food.Taking it with food does not prevent gastrointestinal upset, which is another possible side effect of clopidogrel.
Choice D is wrong because clopidogrel does not affect blood pressure.However, having high blood pressure can increase the risk of stroke and other cardiovascular events, so it is important to have it checked regularly and treated if necessary.
Choice E is correct because clopidogrel should be stopped at least 5 days before any planned surgery.This is to reduce the risk of excessive bleeding during or after the surgery.The provider should be informed about the use of clopidogrel and any other medications before undergoing any surgical procedure.
A nurse is preparing to administer alteplase, a thrombolytic drug, to a client who has an acute myocardial infarction. The nurse knows that this drug works by which mechanism?
Explanation
Alteplase works by activating plasminogen, which converts to plasmin, an enzyme that degrades fibrin.Fibrin is a protein that forms the meshwork of a blood clot, so by breaking it down, alteplase helps dissolve the clot and restore blood flow.
Choice A is wrong because alteplase does not inhibit platelet aggregation and adhesion.
Platelets are blood cells that stick together and form the initial plug in a blood clot.Alteplase does not affect platelets directly, but rather targets fibrin.
Choice B is wrong because alteplase does not interfere with the coagulation cascade.
The coagulation cascade is a series of reactions that lead to the formation of fibrin from fibrinogen.Alteplase does not inhibit any of the steps in this process, but rather activates plasminogen, which is already present in the blood.
Choice D is wrong because alteplase does not block the action of platelet activators or receptors.
Platelet activators are substances that stimulate platelets to aggregate and adhere, such as thrombin, ADP, and collagen.
Platelet receptors are molecules on the surface of platelets that bind to these activators or to other platelets, such as GPIIb/IIIa and GPVI.Alteplase does not affect these molecules, but rather targets fibrin.
A nurse is reviewing the medication history of a client who is prescribed cilostazol, an antiplatelet drug, for intermittent claudication. The nurse should recognize that which of the following medications is contraindicated with cilostazol?
Explanation
Omeprazole, a proton pump inhibitor, is contraindicated with cilostazol, an antiplatelet drug, for intermittent claudication.
This is because omeprazole can inhibit the metabolism of cilostazol by affecting the hepatic/intestinal enzyme CYP2C19, which is responsible for converting cilostazol to its active metabolites.This can result in increased plasma levels of cilostazol and increased risk of bleeding and adverse effects.
Choice B is wrong because metoprolol, a beta blocker, is not contraindicated with cilostazol.
Metoprolol can be used to treat hypertension, angina, and heart failure, which are common comorbidities in patients with intermittent claudication.Metoprolol does not interact significantly with cilostazol or affect its metabolism.
Choice C is wrong because simvastatin, a statin, is not contraindicated with cilostazol.
Simvastatin can be used to lower cholesterol and prevent cardiovascular events in patients with intermittent claudication.Simvastatin does not interact significantly with cilostazol or affect its metabolism.
Choice D is wrong because glyburide, a sulfonylurea, is not contraindicated with cilostazol.
Glyburide can be used to treat type 2 diabetes mellitus, which is a common risk factor for intermittent claudication.Glyburide does not interact significantly with cilostazol or affect its metabolism.
A nurse is administering enoxaparin, a low-molecular-weight heparin, to a client who has undergone orthopedic surgery. The nurse should administer this medication by which route and at which site?
Explanation
Subcutaneous injection in the abdomen.This is because enoxaparin is a low-molecular-weight heparin that is administered subcutaneously, usually in the abdomen or outer thigh.The drug should be clear and colorless or pale yellow.The dosage for adults is typically 30mg every 12 hours for 7 to 10 days, or 40mg once a day for 3 weeks after hip replacement surgery.The needle should be inserted fully into the skin and the syringe plunger should be pressed down to inject the drug.Injection sites should be rotated and areas of active skin disease or injury should be avoided.
Choice A is wrong because intramuscular injection in the deltoid muscle is not the recommended route or site for enoxaparin.Intramuscular injection may cause bleeding, bruising, or hematoma formation.
Choice C is wrong because intravenous infusion in a peripheral vein is not the recommended route for enoxaparin.Enoxaparin can be given intravenously only as a bolus injection for acute coronary syndrome, not as an infusion.
Choice D is wrong because intradermal injection in the forearm is not the recommended route or site for enoxaparin.Intradermal injection may cause skin irritation, infection, or necrosis.
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