Anticoagulants, Antiplatelets, & Fibrolytics
How do thrombolytic drugs work?
Promote conversion of plasminogen to plasmin
What is the antidote for heparin?
Protamine sulfate
What is the antidote for low molecular weight anticoagulants?
Protamine sulfate
What are the advantages of dabigatran (Pradaxa) over warfarin? Disadvantages?
*Less bleeding*, faster onset, *no blood work*, *fewer food interactions*, fixed dosing. GI distress, *less experience*, BID dosing, must give on time.
What labs should be monitored while on heparin?
*aPTT*, platelet count, LFTs, renal tests
List three classes of antiplatelet agents.
ASA, P2Y12ADP receptor antagonists, glycoprotein IIb + IIIa receptor antagonists
List drugs which may increase bleeding with heparin.
ASA, antiplatelet drugs, NSAIDS, glucocorticoids
List contraindications to warfarin.
Active bleeding, severe thrombocytopenia, *decreased synthesis of vitamin K (alcoholism, Vitamin K deficiency, liver disease*), surgery of eye, brain, & spinal cord, lumbar puncture or regional anesthesia, *pregnancy & lactation*
Drugs that reduce the formation of fibrin
Anticoagulants
In what part of the vascular system do antiplatelet agents work?
Arteries
What are the two most common anti platelet drugs?
Aspirin, clopidogrel
What factors does heparin deactivate? What does this prevent?
Assists antithrombin in deactivating thrombin & factor Xa to prevent more venous thrombi.
How does heparin work as an anticoagulant?
Assists antithrombin in inactivating thrombin & factor Xa
Which needle length and gauge should the nurse choose to administer subcutaneous heparin? a. ½ inch; 20 gauge b. 5/8 inch; 25 gauge c. 1½ inch; 18 gauge d. 1 inch; 26 gauge
B
How do GP IIb + IIIa receptor antagonists work? Size of effect?
Blocks GP IIb + IIIa receptors & prevents fibrinogen bridges. Large effect, because final step in platelet aggregation.
How does warfarin work as an anticoagulant?
Decreases synthesis of clotting factors dependent on vitamin K
A client is receiving intravenous heparin therapy. The nurse ensures the availability in which of the following medication? A. Acetylcysteine (Mucomyst). B. Calcium gluconate. C. Vitamin K (Mephyton). D. Protamine sulfate.
D
A client with myocardial infarction is receiving tissue plasminogen activator, alteplase (Activase, tPA). While on the therapy, the nurse plans to prioritize which of the following? a. Observe for neurological changes. b. Monitor for any signs of renal failure. c. Check the food diary. d. Observe for signs of bleeding.
D
List signs and symptoms indicative of bleeding?
Decreased BP, increased HR, gum bleeding, bruises, petechiae, hematomas, red or black/tarry stools, discolored/cloudy urine, pelvic pain from ovaries, headache or faintness, lumbar pain from adrenal gland
How does dabigatran (Pradaxa) work?
Directly binds thrombin, which prevents fibrin formation and activation of factor VIII.
How does rivaroxaban (Xarelto) work?
Directly inhibits Factor Xa in clots and serum and inhibits prothrombinase, which prevents fibrin formation.
How does apixaban (Eliquis) work? What is the approved use?
Directly inhibits Factor Xa in clots and serum and inhibits prothrombinase, which prevents fibrin formation. *Prevention of stroke and systemic embolization in nonvalvular atrial fibrillation.*
What factor do low molecular weight anticoagulants deactivate?
Factor Xa
What are the two stages of hemostasis?
Formation of platelet plug, reinforcement of platelet plug with fibrin (coagulation).
Which anticoagulant can be given during pregnancy?
Heparin
What are the 3 anticoagulants?
Heparin, warfarin, dabigatran
How is warfarin distributed? Can it enter the placenta or breast milk?
Highly-protein bound, crosses placenta and enters breast milk
How does aspirin work? How long are platelets affected? How many days before surgery should aspirin be stopped?
Inhibits COX-1, decreasing platelet aggregation, and inhibits COX-2, decreasing vasoconstriction. 7-10 days. 7 days.
How does warfarin work?
Interferes with synthesis of Vitamin K-dependent clotting factors
What is the difference in MOA between infractioned heparin and LMW heparin?
LMW Heparin acts on factor Xa, whereas normal heparin affects thrombin and factor Xa
Arterial thrombi cause what kind of injury?
Local injury
What is the common LMW heparin?
Lovenox
Discuss the proper administration of heparin SubQ.
Lower abdomen, rotate sites, no rubbing, no aspiration. 2" from umbilicus, 25-26 gauges, 1/2 to 5/8 needle, gentle, firm pressure for 1-2 min after.
What would you tell a patient on warfarin who wants to take Tylenol?
Need to monitor INR - 4 325 mg tablets a day for one week can increase risk of elevated INR by 10X (May need to lower warfarin dose)
Can Warfarin be used during pregnancy and lactation?
No
Does LMW heparin require aPTT monitoring?
No
What two labs are used to monitor warfarin therapy? What is the suggested range?
PT & INR. INR 2-3 (3-4.5 if mechanical heart valve)
What two labs must be monitored while taking Wafarin?
PT and INR
What labs should be monitored for bleeding?
PTT, PT, INR, CBC (RBC count, platelet count, HGB, Hematocrit)
Antidote for dabigatran
Praxbind
What is the major adverse effect of thrombolytic therapy?
Serious bleeding
What foods are high in vitamin K?
Spinach, kale, lettuce, turnips, greens, cabbage, watercress, peas, asparagus, broccoli, oats, whole wheat, green tea, mayonnaise, canola oil, soybean oil.
Which thrombolytic drug is administered as a single IV bolus?
Tenectaplase (TKNase)
Which anticoagulant is Pregnancy Category X?
Warfarin (Coumadin)
List contraindications to heparin.
Thrombocytopenia, uncontrollable bleeding, surgery of eye, brain, or spinal cord, lumbar puncture or regional anesthesia
-ase
Thrombolytic drugs (ex. Alteplase)
What is a significant adverse blood dyscrasia that may be caused by the ADP receptor antagonist, clopidogrel (Plavix)? What drugs may prevent its action?
Thrombotic thrombocytopenia purpura (TTP). Proton inhibitors may inhibit CYP2C19, which activates clopidogrel (Plavix).
Where in the vascular system does warfarin work?
Veins
What is the antidote for warfarin?
Vitamin K (phytonadione)
What two drugs increase the synthesis of Vitamin K-dependent clotting factors?
Vitamin K, oral contraceptives
Which lab is used to monitor heparin? What is the recommended range?
aPTT 1.5-2X the control 60-80 s
The laboratory calls to report a drop in the platelet count to 90,000/mm3 for a patient receiving heparin for the treatment of postoperative deep vein thrombosis. Which action by the nurse is the most appropriate? a. Notify the healthcare provider to discuss the reduction or withdrawal of heparin. b. Call the healthcare provider to discuss increasing the heparin dose to achieve a therapeutic level. c. Obtain vitamin K and prepare to administer it by intramuscular (IM) injection. d. Observe the patient and monitor the activated partial thromboplastin time (aPTT) as indicated.
A (Heparin-induced thrombocytopenia (HIT) is a potential immune-mediated adverse effect of heparin infusions that can prove fatal. HIT is suspected when the platelet counts fall significantly. A platelet count below 100,000/mm3 would warrant discontinuation of the heparin.)
A client is receiving a continuous infusion of streptokinase (Streptase). The client suddenly complaints of a difficulty of breathing, itchiness, and nausea. Which of the following should be the priority action of the nurse? A. Stop the infusion and notify the physician. B. Administer protamine sulfate and provide oxygen therapy. C. Administer antihistamine then continue the infusion. D. Slow the infusion and administer oxygen.
A (Severe allergic reaction to streptokinase requires immediate discontinuation of Streptokinase,then notify the physician and administer an adrenergic, antihistamine, and/or corticosteroid agents as ordered.)
Name the three categories of drugs for thromboembolic disorders? Where in the vascular system do they work?
Anticoagulants - veins. Antiplatelet agents - arteries. Thrombolytics - veins or arteries
A client with atrial fibrillation is receiving a continuous heparin infusion at 1,000 units/hr. The nurse observes that the client is receiving the therapeutic effect based on which of the following results? A. Activated partial thromboplastin time of 30 seconds. B. Activated partial thromboplastin time of 60 seconds. C. Activated partial thromboplastin time of 120 seconds. D. Activated partial thromboplastin time of 15 seconds.
B
How do ADP receptor antagonists work? How long are platelets affected?
Block ADP receptors and prevents platelet aggregation (clopidogrel- Plavix). 7-10 days, take off 5 days prior to surgery.
A patient presents to the emergency department with symptoms of acute myocardial infarction. After a diagnostic workup, the healthcare provider prescribes a 15-mg IV bolus of alteplase (tPA), followed by 50 mg infused over 30 minutes. In monitoring this patient, which finding by the nurse most likely indicates an adverse reaction to this drug? a. Urticaria, itching, and flushing b. Blood pressure of 90/50 mm Hg c. Decreasing level of consciousness d. Potassium level of 5.5 mEq/L
C (The greatest risk with this drug is bleeding, with intracranial bleeding being the greatest concern. A decreasing level of consciousness indicates intracranial bleeding. Alteplase does not cause an allergic reaction or hypotension. Thrombolytic agents, such as alteplase, do not typically cause an elevated potassium level.)
The nurse is caring for a patient who takes warfarin [Coumadin] for prevention of deep vein thrombosis. The patient has an international normalized ratio (INR) of 1.2. Which action by the nurse is most appropriate? a. Administer intravenous (IV) push protamine sulfate. b. Continue with the current prescription. c. Prepare to administer vitamin K. d. Call the healthcare provider to increase the dose.
D (An INR in the range of 2 to 3 is considered the level for warfarin therapy. For a level of 1.2, the nurse should contact the healthcare provider to discuss an order for an increased dose.)
Venous thrombi cause what type of injury?
Distal injury
This drug activates antithrombin, a protein that inactivates two major clotting factors, thrombin and factor Xa
Heparin
What potentially-fatal disorder occurs with heparin?
Heparin induced thrombocytopenia (HIT)
A patient is being discharged from the hospital on warfarin [Coumadin] for deep vein thrombosis prevention. Which instructions should the nurse include in the patient's discharge teaching plan? (Select all that apply.) a. Wear a medical alert bracelet. b. Check all urine and stool for discoloration. c. Do not start any new medication without first talking to your healthcare provider. d. Enteric-coated aspirin and any aspirin products can be used unless they cause a gastrointestinal ulcer. e. No laboratory or home monitoring of international normalized ratio (INR) is required after the first 6 months.
A B C (Advise the patient to wear some form of identification (eg, Medic Alert bracelet) to alert emergency personnel to warfarin use. Bleeding is a major complication of warfarin therapy. Inform patients about the signs of bleeding, which include discolored urine or stools. Inform patients that warfarin is subject to a large number of potentially dangerous drug interactions. Instruct them to avoid all prescription and nonprescription drugs that have not been specifically approved by the prescriber. Aspirin and aspirin products should be avoided because aspirin can increase the effects of warfarin to promote bleeding and on the gastrointestinal tract to cause ulcers, thereby initiating bleeding. The INR should be determined frequently: daily during the first 5 days, twice a week for the next 1 to 2 weeks, once a week for the next 1 to 2 months, and every 2 to 4 weeks thereafter.)
A patient is receiving a continuous heparin infusion for venous thromboembolism treatment. Which laboratory results should the nurse monitor? (Select all that apply.) a. Platelets b. Vitamin K c. Prothrombin time (PT) d. International normalized ratio (INR) e. Activated partial thromboplastin time (aPTT)
A E (To reduce the risk of heparin-induced thrombocytopenia (HIT), platelet counts should be monitored. Heparin therapy is monitored by measuring the laboratory test activated partial thromboplastin time (aPTT). Warfarin therapy is monitored by measuring prothrombin time (PT) and results are expressed as an international normalized ratio (INR). Vitamin K is not monitored for a heparin infusion.)
A nurse is providing instructions to a client who is receiving warfarin sodium (Coumadin). Which statement made by the client indicates the need for further instruction? A. "I will observe the color of my urine and stool". B. "I will take Ecotrin (Enteric coated aspirin) for my headaches". C. "I will avoid drinking alcohol". D. "I will take the medicine daily at the same time".
B
Your pregnant patient is going to be started on anticoagulant therapy. Which of the following medications do you suspect your patient to be prescribed? a. Warfarin b. Heparin c. Aspirin d. Alteplase
B
A nurse is caring for a client receiving a heparin intravenous (IV) infusion. The nurse expects that which of the following laboratory will be prescribed to monitor the therapeutic effect of heparin? A. Prothrombin time (PT). B. Activated partial thromboplastin time (Aptt). C. Hematocrit (Hgb). D. Hemoglobin (Hct).
B (Activated partial thromboplastin time assess the therapeutic level of heparin. Option A: Assess the therapeutic level of warfarin sodium (Coumadin). Options C and D: Measures the aspect of the red blood cells.)
A nurse is providing health teachings regarding antiplatelet medications. Which of the following is not true regarding the use of this medication? a. Antiplatelet medication inhibits the aggregation of platelets in the clotting process, thereby prolonging bleeding time. b. Antiplatelet medications cannot be used with anticoagulants. c. Take the medication with food to prevent gastrointestinal upset. d. A routine bleeding time is monitored during the therapy.
B (Antiplatelet and anticoagulant therapies are effective in keeping a clot from forming or stopping the growth of one.)
A patient with a deep vein thrombosis receiving an intravenous (IV) heparin infusion asks the nurse how this medication works. What is the nurse's best response? a. Heparin prevents the activation of vitamin K and thus blocks synthesis of some clotting factors. b. Heparin suppresses coagulation by helping antithrombin perform its natural functions. c. Heparin works by converting plasminogen to plasmin, which in turn dissolves the clot matrix. d. Heparin inhibits the enzyme responsible for platelet activation and aggregation within vessels.
B (Heparin is an anticoagulant that works by helping antithrombin inactivate thrombin and factor Xa, reducing the production of fibrin and thus decreasing the formation of clots.)
The nurse is caring for a patient receiving clopidogrel [Plavix], a thrombolytic, to prevent blockage of coronary artery stents. Which other drug on the patient's medication administration record may reduce the antiplatelet effects of clopidogrel? a. Aspirin [Bayer] b. Omeprazole [Prilosec] c. Acetaminophen [Tylenol] d. Warfarin [Coumadin]
B (Omeprazole and other proton pump inhibitors may reduce the antiplatelet effects of clopidogrel. Patients sometimes take them to reduce gastric acidity and the risk of gastrointestinal (GI) bleeding.)
A patient diagnosed with a pulmonary embolism is receiving a continuous heparin infusion at 1000 units/hr. Of which findings should the nurse immediately notify the healthcare provider? (Select all that apply.) a. aPTT of 65 seconds b. aPTT of 40 seconds c. Nosebleeds d. aPTT of 100 seconds e. Platelet count of 300,000/mcL
B C D (Measurement of the aPTT is essential to determine whether the heparin infusion is having the desired effect. If the normal value of the aPTT is 40 seconds, the goal is to achieve a therapeutic range of a factor of 1.5 to 2 (60 to 80 seconds). Because 40 seconds is too short (increases the risk for clotting) and 100 seconds is too long (increases the risk for bleeding), the physician requires notification for adjustment of the infusion rate. Evidence of bleeding, such as nosebleeds, hematuria, and red or tarry stools, warrant a call to the physician. An aPTT of 65 seconds indicates that a therapeutic effect has been achieved, and a platelet count of 300,000/mcL is within normal limits, indicating no evidence of thrombocytopenia.)
Which instruction about clopidogrel [Plavix] should the nurse include in the discharge teaching for a patient who has received a drug-eluting coronary stent? a. "Constipation is a common side effect of clopidogrel, so take a stool softener daily." b. "If you see blood in your urine or black stools, stop the clopidogrel immediately." c. "Check with your healthcare provider before taking any over-the-counter medications for gastric acidity." d. "Keep the amounts of foods containing vitamin K, such as mayonnaise, canola and soybean oil, and green, leafy vegetables, consistent in your diet."
C (Proton pump inhibitors (PPIs), such as omeprazole [Prilosec], and CYP2C1 inhibitors, such as cimetidine [Tagamet], can be purchased over the counter to treat heartburn. However, patients taking clopidogrel should consult their healthcare provider before using them. PPIs and CYP2C1 inhibitors can reduce the antiplatelet effects of clopidogrel. Diarrhea (5% incidence), not constipation, is a side effect of clopidogrel. Patients should immediately contact their healthcare provider if signs of bleeding occur, such as bloody urine, stool, or emesis. The drug should not be stopped until the prescriber advises it, because this could lead to coronary stent restenosis. Consistency of vitamin K intake is indicated while taking warfarin [Coumadin].)
The nurse is monitoring a patient receiving a heparin infusion for the treatment of pulmonary embolism. Which assessment finding most likely relates to an adverse effect of heparin? a. Heart rate of 60 beats per minute b. Blood pressure of 160/88 mm Hg c. Discolored urine d. Inspiratory wheezing
C (The primary and most serious adverse effect of heparin is bleeding. Bleeding can occur from any site and may be manifested in various ways, including reduced blood pressure, increased heart rate, bruises, petechiae, hematomas, red or black stools, cloudy or discolored urine, pelvic pain, headache, and lumbar pain.)
A client with deep vein thrombosis is receiving Streptokinase (Streptase). The nurse would notify the physician if which of the following assessment is noted? A. A temperature of 99.2° Fahrenheit. B. A pulse rate of 99 beats per minute. C. A respiratory rate of 25 breaths per minute. D. A blood pressure of 185/110 mm Hg.
D (Thrombolytic therapy is contraindicated with uncontrolled hypertension (systolic BP >180 mm Hg and/or diastolic BP >110 mm Hg) because of the risk of cerebral hemorrhage. Options A, B, and C may be present during the therapy but will not warrant the immediate knowledge of the physician before starting the therapy.)
