PNE+174+Basic+Pharmacology+for+Nurses.Chapter_027.AR

CHAPTER 27: DRUGS USED TO TREAT THROMBOEMBOLIC DISORDERS

  • Source: Clayton’s Basic Pharmacology for Nurses, 20th Edition

  • Author: Michelle J. Willihnganz, MS, RN, CNE

LEARNING OBJECTIVES

  • Describe Conditions at Risk for Blood Clots:

    • Identify conditions that predispose individuals to the formation of blood clots.

    • Discuss nursing interventions used to prevent these conditions.

  • Identify Actions of Various Agents:

    • Describe the actions of:

      • Platelet inhibitors

      • Factor Xa inhibitors

      • Thrombin inhibitors

      • Fibrinolytic agents

  • Monitoring Procedures for Hemorrhage:

    • Describe specific monitoring procedures and laboratory data used to detect hemorrhage in patients on anticoagulants.

  • Nursing Assessments for Monitoring Response:

    • Describe nursing assessments necessary for monitoring therapeutic response and adverse effects from anticoagulant therapy.

THROMBOEMBOLIC DISORDERS

  • Definition:

    • Disorders involving the formation of a blood clot (thrombus) which can fragment and create an embolus circulating until trapped in a capillary.

  • Clotting Cascade Activation:

    • Activated by:

      • Injury to a blood vessel

      • Increased viscosity of blood

  • Pathways of Clotting:

    • Intrinsic Clotting Pathway

    • Extrinsic Clotting Pathway

NONPHARMACOLOGIC TREATMENT OF THROMBOEMBOLIC DISORDERS

  • Prevention of Conditions that Cause CLOTS:

    • Risk factors include immobility, venous stasis, certain medical conditions such as:

      • Surgery, trauma to lower limbs

      • Heart failure

      • Vasospasm

      • Various cancers (lung, prostate, stomach, pancreas)

      • Pregnancy and oral contraceptive use

  • Strategies to Prevent Stasis:

    • Methods:

      • Leg exercises

      • Wearing compression stockings

      • Leg elevation techniques

      • Sequential compression devices

      • Revascularization treatments such as:

        • Percutaneous coronary intervention

        • Coronary artery bypass grafting

DRUG THERAPY GOALS FOR THROMBOEMBOLIC DISORDERS

  • Primary Purpose:

    • Prevent platelet aggregation and inhibit steps in the clotting cascade.

  • Types of Agents:

    • Platelet Inhibitors

    • Anticoagulants

    • Glycoprotein IIB/IIIA Inhibitors

    • Thrombolytics

  • Anticoagulation Therapy:

    • Prevents new clot formation and extension of existing clots.

LABORATORY TESTS FOR THROMBOEMBOLIC DISORDERS

  • Coagulation Tests:

    • PT (Prothrombin Time): Monitors warfarin therapy.

    • APTT (Activated Partial Thromboplastin Time): Monitors heparin therapy.

    • INR (International Normalized Ratio): Also monitors warfarin.

  • Platelet Counts:

    • Important diagnostic indicator.

  • Diagnostic Tests Include:

    • PT, APTT, Hematocrit, Platelet Count, Doppler studies, Exercise testing, Serum triglycerides, Arteriogram, Cardiac enzyme studies.

NURSING IMPLICATIONS

  • Assessment Components:

    • Obtain patient history, current symptoms, and medications.

    • Perform basic assessment including:

      • Vital signs

      • Auscultation of breath sounds

      • Check mental status

      • Assess for reduced tissue perfusion signs

      • Collect data on any pain experienced

      • Verify hydration state

PATIENT EDUCATION FOR ANTICOAGULATION THERAPY

  • Diet and Nutrition:

    • Limit intake of leafy green vegetables known to affect anticoagulant activity.

    • Recommended fluid intake: Six to eight 8-ounce glasses per day.

  • Post-surgery Exercise and Activity Recommendations:

    • Engage in activities to prevent venous stasis.

    • Avoid flexing knees or placing pressure under knees and avoid prolonged immobility.

  • Medication Regimen Education:

    • Emphasize the importance of wearing a medical alert bracelet.

    • Inform about dosing and timing, common and serious adverse effects, and drug interactions.

    • Encourage reporting any signs of bleeding.

DRUG CLASS: PLATELET INHIBITORS

  • Includes:

    • Drugs:

      • Aspirin

      • Dipyridamole (Persantine)

      • Clopidogrel (Plavix)

      • Ticlopidine (Ticlid)

  • Actions:

    • Non-steroidal anti-inflammatory drug (NSAID) that inhibits platelet aggregation.

  • Uses:

    • Reduces the risk of myocardial infarction (MI) in men.

    • Reduces the risk of stroke in women.

    • Commonly used in men and women with acute MI.

  • Common Adverse Effects:

    • Abdominal distress, hypotension.

  • Serious Adverse Effects:

    • Neutropenia, agranulocytosis, bleeding.

    • Clopidogrel can cause Thrombotic Thrombocytopenic Purpura (TTP).

DRUG CLASS: FACTOR XA INHIBITORS

  • Includes:

    • Apixaban, Rivaroxaban, Edoxaban.

  • Uses:

    • Reduce risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation.

    • Betrixaban for preventing DVT and PE in acute medical illness patients at risk for thromboembolic complications.

  • Common Adverse Effect:

    • Bleeding.

DRUG CLASS: ANTICOAGULANTS

  • Low-Molecular-Weight Heparins Include:

    • Dalteparin (Fragmin), Enoxaparin (Lovenox), Fondaparinux (Arixtra).

  • Uses:

    • Prevent DVT after hip replacements or abdominal surgery; prevent MIs combined with aspirin.

  • Common Adverse Effects:

    • Hematoma formation, bleeding at injection site.

  • Serious Adverse Effects:

    • Bleeding, thrombocytopenia.

ENOXAPARIN ADMINISTRATION TECHNIQUE

  • Method:

    • Subcutaneous injection into anterolateral or posterolateral abdominal wall every 12-24 hours.

  • Instructions:

    • Do not expel the air bubble from the prefilled syringe prior to injection.

    • Inject the entire needle into the skin fold, inject slowly, and keep the needle in place for 10 seconds post-injection.

    • Do not rub the injection site, and alternate sites for injections.

DRUG CLASS: HEPARIN

  • Action:

    • In the presence of heparin, antithrombin III neutralizes thrombin and factors IXA, XA, XI, and XII; assists plasmin in digestion effectiveness.

  • Uses:

    • Treatment of DVT, pulmonary embolism, cerebral embolism.

  • Administration Routes:

    • Subcutaneously, IV push, IV infusion with varying dosages.

  • Monitoring Requirements:

    • Monitor aPTT, platelets, hematocrit.

  • Common Adverse Effects:

    • Hematoma formation, bleeding at injection site.

  • Serious Adverse Effects:

    • Bleeding, thrombocytopenia.

HEPARIN ADMINISTRATION

  • Safe Practices:

    • Confirm dosage calculations with another nurse.

    • Ensure dose strength is correct.

    • Therapeutic range for aPTT is 1.5 to 2.5 times the control.

  • Injection Techniques:

    • Administer subcutaneously into abdomen, do not massage site, alternate injection sites, use a 90-degree angle, apply gentle pressure post-injection.

  • Common Adverse Effects to Monitor:

    • Bleeding or hematoma at injection site.

  • Serious Adverse Effects:

    • Monitor for bleeding from mucous membranes, skin, urine, and stools; thrombocytopenia; internal bleeding.

DRUG CLASS: WARFARIN (COUMADIN)

  • Action:

    • Inhibits activity of vitamin K that activates certain clotting factors.

  • Uses:

    • Treatment/prophylaxis of DVT, embolization from atrial fibrillation, pulmonary embolism, and heart valve replacement.

  • Target INR:

    • INR of 2 to 3 for patients with atrial fibrillation, stroke, MI, and DVT.

    • INR of 2.5 to 3.5 for patients with mechanical heart valve devices.

  • Adverse Effects:

    • Bleeding—monitor skin, mucous membranes, internal bleeding, urine and stool appearance, menstrual flow, surgical dressings.

    • Contraindications: Pregnancy.

    • Antidote: Discontinue use and administer vitamin K.

    • Caution: Note numerous drug interactions.

COUMADIN: PREMEDICATION ASSESSMENT

  • Check:

    • Most recent PT/INR and assess for signs of bleeding.

  • Dietary Education:

    • Foods high in vitamin K, such as green leafy vegetables, should be reviewed.

  • Dosing Information:

    • Available in various dosages: 2-5 mg/day initially; 2-10 mg/day maintenance.

  • Importance of Compliance:

    • Emphasize the need to comply with regimen and need for laboratory data monitoring.

CORRECT DOSING IMPORTANCE

  • Key Points:

    • Critical for controlling clots.

    • Use the Medication Administration Record for scheduling.

    • Mark one-time dosages clearly.

    • Do not administer anticoagulants before checking the chart for recent laboratory results.

AUDIENCE RESPONSE QUESTIONS

  • Question 1:

    • For blood clots to form post-surgical incision, which pathway is triggered?

      • Options: Thrombotic, Intrinsic, Extrinsic, Embolic.

  • Question 2:

    • A patient with DVT is discharged on enoxaparin. Which statement indicates a need for further instruction?

      • “I’ll massage the spot I inject so the drug will absorb.”

  • Question 3:

    • Which laboratory test measures the effectiveness of heparin?

      • Answer: aPTT

  • Question 4:

    • Reason for the patient receiving both warfarin and heparin?

      • “Heparin is often used to initiate therapy; oral anticoagulants are adjusted until adequate therapeutic response is indicated.”

  • Question 5:

    • Which drug class can dissolve blood clots?

      • Answer: Thrombolytic agents.

DRUG CLASS: THROMBIN INHIBITOR

  • Drug:

    • Dabigatran (Pradaxa)

  • Action:

    • Direct thrombin inhibitor that prevents conversion of fibrinogen to fibrin.

  • Usage:

    • Reduces risk of stroke with nonvalvular atrial fibrillation.

  • Premedication Assessments:

    • Monitor for bleeding; check laboratory values and consider pregnancy risk.

DABIGATRAN

  • Safety Alert:

    • Capsules must be swallowed whole and are sensitive to moisture.

    • The bottle must be used within 30 days of opening.

  • Adverse Effects:

    • Risk of bleeding.

DRUG CLASS: GLYCOPROTEIN IIB/IIIA INHIBITORS

  • Drugs Include:

    • Abciximab (Reopro), Eptifibatide (Integrilin), Tirofiban (Aggrastat).

  • Action: