Anticoagulants Flashcards
Which anticoagulant has a delayed onset of action?
Warfarin
D. Inhibits epoxide reductase to decrease Vitamin K.
C. Vitamin K and FFPD
C. Factor VII
A. Erythromycin.
D. Rifampin
A. Apixaban
Each of the following anticoagulants decreases factor Xa activity EXCEPT?
A. Apixaban
B. Dabigatran
C. Fondaparinux
D. Unfractionated Heparin
B. Dabigatran is a direct thrombin inhibitor and directly binds and inhibits thrombin/factor II and does not decrease the activity of factor Xa.
Which of the following anticoagulants requires monitoring of the PTT (partial thromboplastin time)?
A. Abciximab
B. Enoxaparin
C. Rivaroxaban
D. Unfractionated heparin
D. Unfractionated heparin is monitored with PTT or aPTT.
Which of the following is a contraindication to the administration of enoxaparin for DVT treatment?
A. Inability to take oral meds
B. Pregnancy
C. Recent major trauma
D. Renal failure
D. Renal Failure. Enoxaparin is a LMWH and is renally eliminated and has a longer hal-life, therefore contraindicated in renal failure patients.
Which of the following clinical signs is the most appropriate for initiating aspirin therapy?
A. Acute ischemic stroke.
B. Acute MI
C. Closure of a patent ductus arteriosus
D. Initial Tx of PE
B. Acute MI
A patient receiving heparin for treatment of deep vein thrombosis (DVT) has an elevated activated partial thromboplastin time (aPTT) slightly over the therapeutic range. He has no evidence of bleeding. Which action is recommended to reduce risk for bleeding and achieve a therapeutic level?
A. Temporarily holding the drug and reducing the dose
B. Administering protamine sulfate 1 mg for every 100 units
C. Administering vitamin K
D. Administering platelets
A. Because heparin’s half-life is short, heparin overdose is usually treated with withdrawal of the drug.
A patient taking warfarin for a history of deep vein thrombosis presents with an international normalized ratio (INR) of 4.2. His examination shows no evidence of bleeding. Which action taken by the APN is most appropriate?
A. Stop the warfarin and begin treatment with a direct factor Xa inhibitor.
B. Treat with 2 mg of vitamin K and adjust the dose accordingly.
C. Treat with protamine sulfate and adjust the dose accordingly.
D. Hold one or more doses, recheck the INR and adjust the dose accordingly
D. Toxicity and overdose are usually treated by withholding one or two doses of warfarin.
Which agent is categorized as a direct thrombin inhibitor?
A. Fondaparinux (Arixtra)
B. Dabigatran (Pradaxa)
C. Rivaroxaban (Xarelto)
D. Low molecular weight heparin (LMWH)
B. Dabigatran works as a direct thrombin inhibitor to prevent conversion of fibrinogen to fibrin to prevent thrombus formation. Fondaparinux is a selective antithrombin III inhibitor and factor Xa inhibitor. Rivaroxaban is a factor Xa inhibitor and selectively inactivates circulating factor Xa, reducing thrombin formation. LMWH potentiates activity of antithrombin III and inactivates factors Xa and IIa (thrombin).
An elderly patient with a history of atrial fibrillation on dabigatran presents with gastrointestinal bleeding. The APN reviews the patient’s current medications. Which medication is most likely to cause a significantly increased risk for bleeding when combined with dabigatran?
A. Hydrochlorothiazide taken to reduce blood pressure
B. Metoprolol taken for heart rate control
C. Aspirin taken for arthritis pain
D. Diltiazem used for heart rate control
C. Drugs that affect platelet functioning, including aspirin, increase risk for bleeding with any anticoagulant.