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Chapter 20: Anticoagulant, Antiplatelet, and Thrombolytic Drugs

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Chapter 20: Anticoagulant, Antiplatelet, and Thrombolytic Drugs

12 problems · 0 figures

Case Study 20.2.1 §20.2 source ↗

Read the following clinical scenario to answer the questions that follow.

Thomas Schmidt, a 48-year-old client, presents to the emergency department with reports of stabbing chest pain and is diagnosed with pulmonary embolism using computed tomography pulmonary angiography. Thomas is started on heparin. He is given an initial dose of 80 units/kg IV as a bolus, then started on a continuous infusion of 18 units/kg/hour.

History
Diabetes mellitus type 2

Current Medications
Metformin 500 mg orally daily

After 6 hours, a PTT is checked and the result is 75 seconds. Using the sample algorithm in Table 20.2, how will the nurse adjust the dose?
  1. a.
    80 units/kg bolus, then increase rate by 4 units/kg/hr; recheck in 6 hours
  2. b.
    40 units/kg bolus, then increase rate by 2 units/kg/hr; recheck in 6 hours
  3. c.
    Decrease infusion rate by 2 units/kg/hr; recheck in 6 hours
  4. d.
    Interrupt infusion for 1 hour, then decrease infusion rate by 3 units/kg/hr; recheck in 6 hours
Table 20.4 in the book ↗
Vital Signs Physical Examination
Temperature: 98.6°F

• Head, eyes, ears, nose, throat (HEENT): Denies any changes in vision. No difficulty hearing conversations.

• Cardiovascular: No jugular vein distention or pedal edema noted; S1, S2 heard on auscultation. Denies chest pain. Capillary refill brisk, mucous membranes pink and moist.

• Respiratory: Lungs clear to auscultation. Describes 8/10 stabbing chest pain.

• GI: Abdomen soft, nontender, nondistended; bowel sounds heard in all four quadrants. No report of nausea, vomiting, or abdominal pain. Has regular daily bowel movements.

• GU: Deferred.

• Neurological: Alert and oriented to time, place, person, and events.

• No reports of numbness, dizziness, vertigo, weakness, or seizures.

• Integumentary: No wounds noted; skin appropriate for age.
Blood pressure: 125/85 mm Hg
Heart rate: 90 beats/min
Oxygen saturation: 98% on room air
Height: 5'10"
Weight: 253 lb
Table 20.2 in the book ↗
Drug Routes and Dosage Ranges
Heparin Complicated and variable. Typical starting dose 18 units/kg/hr administered by continuous intravenous (IV) infusion, titrate to goal PTT or anti-Xa range. See Table 20.3 for sample heparin titration protocol. (Protocols are usually site specific and should be utilized accordingly.)
Venous prophylaxis of thromboembolism in acutely ill medical clients: 5000 units subcutaneously every 8 hours.
Argatroban Complicated and variable. Typical starting dose 2 mcg/kg/min administered as a continuous IV infusion, titrate to goal PTT. (Protocols are usually site specific and should be utilized accordingly.)
Bivalirudin
(Angiomax)		 Treatment of heparin-induced thrombocytopenia (off-label): Starting dose 0.15–0.20 mg/kg/hr as a continuous IV infusion, titrate to PTT goal.
Enoxaparin
(Lovenox)		 Treatment of venous thromboembolism: 1 mg/kg subcutaneously every 12 hours.
Venous thromboembolism prophylaxis in acutely ill medical clients: 40 mg subcutaneously once daily.
Dalteparin
(Fragmin)		 Treatment of deep vein thrombosis or pulmonary embolism: 200 units/kg subcutaneously once daily or 100 units/kg subcutaneously twice daily.
Warfarin
(Coumadin)		 Complicated and variable. Dietary considerations for vitamin K content must be considered. Typical initial dose: 5 mg daily. Titrate to goal INR range (commonly 2–3).
Apixaban
(Eliquis)		 Atrial fibrillation: 5 mg orally twice daily.
Treatment of deep vein thrombosis or pulmonary embolism: 10 mg orally twice daily for 7 days, followed by 5 mg twice daily.
Rivaroxaban
(Xarelto)		 Atrial fibrillation: 20 mg orally once daily with the evening meal.
Treatment of deep vein thrombosis or pulmonary embolism: 15 mg orally twice daily with food for 21 days, followed by 20 mg once daily with food.
Edoxaban
(Savaysa)		 Atrial fibrillation: 60 mg orally once daily.
Treatment of deep vein thrombosis: 60 mg orally once daily for clients >60 kg or 30 mg orally once daily for clients ≤60 kg (after at least 5 days of parenteral anticoagulation).
Dabigatran
(Pradaxa)		 Atrial fibrillation: 150 mg orally twice daily.
Treatment of deep vein thrombosis: 150 mg orally twice daily (after at least 5 days of parenteral therapy).
Drug Emphasis Table: Anticoagulants (sources: https://dailymed.nlm.nih.gov/dailymed/; Linkins et al., 2012; Jaff et al., 2011)

Answer

C. Decrease infusion rate by 2 units/kg/hr; recheck in 6 hours
The PTT is 75 seconds. Per the protocol, any PTT between 71 and 90 seconds will require a decrease in the heparin rate by 2 units/kg/hour.

Case Study 20.2.2 §20.2 source ↗

Read the following clinical scenario to answer the questions that follow.

Thomas Schmidt, a 48-year-old client, presents to the emergency department with reports of stabbing chest pain and is diagnosed with pulmonary embolism using computed tomography pulmonary angiography. Thomas is started on heparin. He is given an initial dose of 80 units/kg IV as a bolus, then started on a continuous infusion of 18 units/kg/hour.

History
Diabetes mellitus type 2

Current Medications
Metformin 500 mg orally daily

The nurse is providing discharge teaching for Thomas, who will use low molecular weight heparin (LMWH) injections at home. Which of the following statements about LMWH therapy will the nurse include in the teaching plan?
  1. a.
    More frequent lab assessments are required with LMWH therapy.
  2. b.
    The duration of action is 2–4 times longer than heparin.
  3. c.
    The risks for bleeding are less.
  4. d.
    LMWH is more likely to cause thrombocytopenia.
Table 20.4 in the book ↗
Vital Signs Physical Examination
Temperature: 98.6°F

• Head, eyes, ears, nose, throat (HEENT): Denies any changes in vision. No difficulty hearing conversations.

• Cardiovascular: No jugular vein distention or pedal edema noted; S1, S2 heard on auscultation. Denies chest pain. Capillary refill brisk, mucous membranes pink and moist.

• Respiratory: Lungs clear to auscultation. Describes 8/10 stabbing chest pain.

• GI: Abdomen soft, nontender, nondistended; bowel sounds heard in all four quadrants. No report of nausea, vomiting, or abdominal pain. Has regular daily bowel movements.

• GU: Deferred.

• Neurological: Alert and oriented to time, place, person, and events.

• No reports of numbness, dizziness, vertigo, weakness, or seizures.

• Integumentary: No wounds noted; skin appropriate for age.
Blood pressure: 125/85 mm Hg
Heart rate: 90 beats/min
Oxygen saturation: 98% on room air
Height: 5'10"
Weight: 253 lb

Answer

B. The duration of action is 2–4 times longer than heparin.
One of the advantages of LMWH is the longer duration of action, which means that once-daily injections, instead of continuous infusion, are effective.

20-1 §20.RQ source ↗

The nurse admits a client with an acute pulmonary embolism and is instructed to start heparin. Which of the following tests can the nurse best use to adjust the dose of heparin?
  1. a.
    Partial thromboplastin time (PTT)
  2. b.
    International normalized ratio (INR)
  3. c.
    Complete blood count (CBC)
  4. d.
    Prothrombin time (PT)

Answer

A. Partial thromboplastin time (PTT)
Heparin can be monitored by using the partial thromboplastin time or anti-factor Xa level, depending on the institutional protocol.

20-2 §20.RQ source ↗

A client who received heparin developed uncontrollable bleeding. What medication is the provider most likely to use as an antidote to the heparin?
  1. a.
    Protamine
  2. b.
    Phytonadione
  3. c.
    Idarucizumab
  4. d.
    Andexanet alfa

Answer

A. Protamine
Protamine is a protein that works to neutralize heparin.

20-3 §20.RQ source ↗

The nurse is answering the client’s question about the risk for heparin-induced thrombocytopenia (HIT). Which of the following information should be included in the discussion?
  1. a.
    The condition increases the risk for bleeding.
  2. b.
    The platelet count rises above normal initially.
  3. c.
    The condition is immune mediated.
  4. d.
    The skin rash is the most reliable diagnostic indicator.

Answer

C. The condition is immune mediated.
The antibodies decrease the platelet count, leaving the client at risk for the development of thrombosis.

20-4 §20.RQ source ↗

A client is admitted to the emergency department with an acute myocardial infarction. Which medication does the nurse anticipate being ordered to dissolve the clot in the coronary artery?
  1. a.
    Vitamin K
  2. b.
    Alteplase
  3. c.
    Warfarin
  4. d.
    Enoxaparin

Answer

B. Alteplase
Alteplase is a thrombolytic drug used to dissolve clots.

20-5 §20.RQ source ↗

The nurse is teaching a client with a pulmonary embolism about their new medication, heparin. What will the nurse tell the client about the purpose of heparin?
  1. a.
    It will dissolve the blood clot quickly.
  2. b.
    It will prevent platelet-to-platelet adhesion.
  3. c.
    It will enhance clotting.
  4. d.
    It will prevent further clot formation.

Answer

D. It will prevent further clot formation.
Heparin is an anticoagulant. It will prevent further clot formation while the body naturally breaks down the clot, but it will not directly dissolve the clot.

20-6 §20.RQ source ↗

A nurse is teaching a client about warfarin dietary considerations. Which of the following statements by the client indicates understanding of the restrictions?
  1. a.
    “I should eat a lot of spinach every day due to increased vitamin K needs.”
  2. b.
    “I can eat a lot of extra broccoli with a meal as long as it is only occasionally due to decreased vitamin K needs.”
  3. c.
    “I should avoid eating fruit like bananas due to excess vitamin K content.”
  4. d.
    “I should eat a consistent amount of vitamin K–containing foods in my diet.”

Answer

D. “I should eat a consistent amount of vitamin K–containing foods in my diet.”
Clients taking warfarin must maintain a consistent amount of vitamin K in their diet.

20-7 §20.RQ source ↗

A nurse admits a client who has been started on warfarin for a pulmonary embolism. Which test will the nurse monitor to assess warfarin’s effect?
  1. a.
    Partial thromboplastin time (PTT)
  2. b.
    International normalized ratio (INR)
  3. c.
    Complete blood count (CBC)
  4. d.
    Anti-factor Xa level

Answer

B. International normalized ratio (INR)
Warfarin is monitored using the INR, or international normalized ratio.

20-8 §20.RQ source ↗

The nurse is monitoring for medication-related adverse effects in a client receiving heparin. Which of the following would indicate that the client should be assessed for heparin-induced thrombocytopenia (HIT)?
  1. a.
    A decrease in platelet count and concomitant gastrointestinal bleed
  2. b.
    A decrease in platelet count and concomitant deep vein thrombosis
  3. c.
    An increase in platelet count and concomitant intracranial hemorrhage
  4. d.
    An increase in platelet count and concomitant pulmonary embolism

Answer

B. A decrease in platelet count and concomitant deep vein thrombosis
Heparin-induced thrombocytopenia is characterized by a decreased platelet count. Contrary to typical thrombocytopenia, the client is extremely hypercoagulable and often has a thrombosis such as a deep vein thrombosis.

20-9 §20.RQ source ↗

Which of the following direct-acting oral anticoagulant drugs must be taken with food for effective absorption?
  1. a.
    Endoxaban
  2. b.
    Dabigatran
  3. c.
    Rivaroxaban
  4. d.
    Apixaban

Answer

C. Rivaroxaban
This drug is more effectively absorbed when taken with food.

20-10 §20.RQ source ↗

An emergency department nurse is assessing a client with an acute ischemic stroke prior to administering alteplase. Which finding will the nurse need to discuss with the provider prior to administering alteplase therapy?
  1. a.
    Total knee replacement surgery 6 months ago
  2. b.
    Blood pressure of 197/110 mm Hg
  3. c.
    Glucose level of 168 mg/dL
  4. d.
    Past medical history of gastroesophageal reflux disease (GERD)

Answer

B. Blood pressure of 197/110 mm Hg
Severe uncontrolled hypertension is a contraindication to alteplase administration.

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Problems and answers are adapted from Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris and Dorie Weaver, OpenStax, and are used under the CC BY-NC-SA 4.0 licence. Access for free at https://openstax.org/books/pharmacology/pages/1-introduction. Illustrations: Copyright Rice University, OpenStax, under CC BY-NC-SA 4.0 license. This adaptation is released under the same licence, is non-commercial, and is neither affiliated with nor endorsed by OpenStax or Rice University.