Drugs Affecting Blood Coagulation (Part 1)

Drugs Affecting Blood Coagulation  A patient is admitted to the hospital with deep vein thrombosis. A 10,000-unit dose of heparin is administered subcutaneously. What drug does the nurse keep on hand to reverse the effects of heparin if the patient begins to bleed? 1. Antithrombin (Thrombate III) A) Desirudin (Iprivask) B) Protamine sulfate C) Vitamin K D) Ans: C Feedback: The antidote for heparin is protamine sulfate. This drug forms stable salts as soon as it comes in contact with heparin. The reaction immediately reverses heparin’s anticoagulation effects. Vitamin K reverses the effect of warfarin. Antithrombin and desirudin are anticoagulants that would not be administered with heparin. Prior to beginning anticoagulant therapy, the nurse will question the female patient about what? 2. Last menstrual period A) Peptic ulcers B) Urinary tract infection C) Weight D) Ans: B Feedback: The nurse should screen for conditions that could be exacerbated by increased bleeding tendencies, including hemorrhagic disorders, recent trauma, spinal puncture, gastrointestinal (GI) ulcers, recent surgery, intrauterine device placement, tuberculosis, presence of indwelling catheters, and threatened abortion. Beginning anticoagulant therapy with active peptic ulcers could result in severe bleeding. Last menstrual period, urinary tract infection, and weight should not impact anticoagulant therapy. The nurse is caring for a female patient who is nursing her 3-month-old infant. What will the nurse instruct the patient to do prior to starting heparin to treat venous thrombosis? 3. Wait an hour after taking the anticoagulant before feeding the infant. A) Push fluids to clear the drug from her system before feeding the infant. B) C) D) Ans: Find another method of feeding the infant while taking this drug. Continue breast-feeding because heparin does not enter breast milk. D Feedback: Although some adverse fetal effects have been reported with its use during pregnancy, heparin does not enter breast milk, and so it is the anticoagulant of choice if one is needed during lactation. As a result, there is no need to wait an hour, push fluids, or find another method of feeding the baby. The nurse receives a patient having an acute myocardial infarction (MI) to the emergency department. What drug will the nurse administer before transferring the patient to a larger facility? 4. Anagrelide (Agrylin) A) Clopidogrel (Plavix) B) Ticlopidine (Ticlid) C) Tenecteplase (TNKase) D) Ans: D Feedback: Arrange to administer tenecteplase to reduce mortality associated with acute MI as soon as possible after the onset of symptoms because the timing for the administration of tenecteplase is critical to resolve the clot before permanent damage occurs to the myocardial cells. Anagrelide is used to treat essential thrombocytopenia. Clopidogrel is used to treat patients who are at risk for ischemic events; ticlopidine is used to reduce the risk of thrombotic stroke. A nurse is preparing to discharge a patient newly prescribed warfarin (Coumadin). While assessing the patient’s knowledge of the drug, what would indicate that the patient needs further instruction concerning drug therapy? 5. A) B) C) I love to eat homegrown tomatoes in the summer. I take aspirin for my arthritis. I walk 2 miles a day. I drink a glass of wine about once a week. D) Ans: B Feedback: Increased bleeding can occur if a salicylate is taken in combination with warfarin. The nurse will instruct the patient to stop taking aspirin. Walking, eating tomatoes, and drinking an occasional glass of wine should not interfere with the therapeutic effects of warfarin. The nurse is caring for a patient with a fever and severe diarrhea in addition to thrombophlebitis. How will this patient’s condition impact the clotting process? 6. Depleted production of Hageman factor A) Increased production of thrombin B) Activation of plasminogen C) Reduced production of fibrinolysin D) Ans: C Feedback: Plasminogen is the basis for the clot-dissolving system. It is converted to plasmin (fibrinolysin) by several factors including Hageman’s factor, which is factor XII found in circulating blood. Activated thrombin breaks down fibrinogen to form fibrin threads, which form a clot inside the blood vessel. Patients with diarrhea or fever could alter the normal clotting process by, respectively, loss of vitamin K from the intestine or activation of plasminogen. The nurse is caring for a patient who received protamine sulfate in error. The patient is not receiving, and has never received, heparin. What effect does the nurse assess for in this patient? 7. Coagulation effects A) No effect B) Anticoagulant effects C) Antiplatelet effects D) Ans: C Feedback: Paradoxically, if protamine is given to a patient who has not received heparin, it has anticoagulant effects. Protamine is normally used as an antidote to heparin overdose but if heparin was not administered, it does not have coagulation or antiplatelet effects. Since it has anticoagulant effects it cannot be said to have no effect. A patient is being discharged home on warfarin. The discharge teaching by the nurse should include a warning to avoid what? 8. St. John’s wort A) Tarragon B) Ginkgo C) Saw palmetto D) Ans: C Feedback: Many of the herbal remedies are known to alter blood coagulation and should be avoided when taking anticoagulants. Patients taking these drugs should be cautioned to avoid angelica, cat’s claw, chamomile, chondroitin, feverfew, garlic, Ginkgo, goldenseal, grape seed extract, green leaf tea, horse chestnut seed, psyllium, and turmeric. If a patient who is taking an anticoagulant presents with increased bleeding and no other interaction or cause is found, question the patient about the possibility of use of herbal therapies. St. John’s wort, tarragon, and saw palmetto are not implicated as having an interaction with anticoagulants. The nurse administers clopidogrel (Plavix) appropriately to the patient with what condition? 9. Maintaining the patency of grafts A) Treating peripheral artery disease B) Preventing emboli from valve replacements C) Dissolving a pulmonary embolus and improving oxygenation D) Ans: B Feedback: Clopidogrel is used to inhibit platelet aggregation, decreasing the formation of clots in narrowed or injured blood vessels like those found in peripheral artery disease. Maintaining the patency of grafts or preventing emboli from valve replacements would be accomplished using an anticoagulant. Dissolving emboli would be accomplished using streptokinase or a similar enzyme to stimulate the conversion of plasminogen to plasmin. The nurse is caring for a patient who is going home on warfarin (Coumadin). What lab test will the patient require to evaluate therapeutic effects of the drug? 10. Activated partial thromboplastin time (APTT) only A) International normalized ratio (INR) only B) Prothrombin time (PT) and INR C) PT and APTT D) Ans: C Feedback: PT and INR are ordered to evaluate for therapeutic effects of warfarin. Normal values of PT is 1.3 to 1.5 times the control value and the ratio of PT to INR is 2 to 3.5. What drug would the nurse administer for its antiplatelet effects? (Select all that apply.) 11. Ticlid A) Iprivask B) Arixtra C) ReoPro D) Activase E) Ans: A, D Feedback: Antiplatelet agents available for use include abciximab (ReoPro), anagrelide (Agrylin), aspirin, cilostazol (Pletal), clopidogrel (Plavix), dipyridamole (Persantine), eptifibatide (Integrilin), ticlopidine (Ticlid), ticagrelor (Brilinta), and tirofiban (Aggrastat). Iprivask and Arixtra are anticoagulants, and Actuvase is a thrombolytic agent. A 76-year-old patient is receiving IV heparin 5,000 units every 8 hours. An activated thromboplastin time (aPTT) is drawn 1 hour before the 8:00 AM dose; the aPTT is at 3.5 times the control value. What is the nurse’s priority action? 12. Give a larger dose to increase the aPTT. A) Give the dose as ordered and chart the results. B) Check the patient’s vital signs prior to administering the dose. C) Hold the dose and call the result to the physician. D) Ans: D Feedback: The therapeutic level of heparin is demonstrated by an activated partial thromboplastin time (aPTT) that is 1.5 to 3 times the control value. The patient’s value is 3.5 times control, which indicates clotting time is a bit too delayed and the dosage will likely either be reduced or a dosage may be held according to the order received from the physician. It would be inappropriate to give two doses at once, give the dose and chart the results, or simply check the vital signs without holding the dose and calling the physician. The nurse evaluates the effects of warfarin (Coumadin) by monitoring what laboratory test? 13. A) Red blood cell count (RBC) Activated thromboplastin time (APT) B) Prothrombin time (PT) and international normalized ratio (INR) C) Platelet count D) Ans: C Feedback: The warfarin dose is regulated according to the INR. INR is based upon the PT. The other options are incorrect. The nurse discovers a patient receiving warfarin is bleeding. What drug would the nurse prepare to counteract this drug? 14. Vitamin E A) Vitamin K B) Protamine sulfate C) Calcium gluconate D) Ans: C Feedback: Injectable vitamin K is used to reverse the effects of warfarin. Protamine sulfate is used to reverse the effects of heparin. Vitamin E reduces effects of warfarin but is not used for that purpose. Calcium gluconate would not be indicated for this patient. 15. The nurse evaluates that additional patient teaching is needed regarding anticoagulants when the patient states that he will do what? Carry a Medic Alert card with him. A) Report to the lab once a month. B) C) D) Ans: Use acetaminophen for arthritis pain. Use a disposable safety razor to shave. D Feedback: The patient should use an electric razor to shave rather than a disposable razor that could nick his skin and increase risk of bleeding. Carrying a MedicAlert card, getting regular follow-up lab work, and use of acetaminophen would all be appropriate actions that would not indicate the need for further teaching. The nurse teaches the patient taking warfarin (Coumadin) to minimize foods high in vitamin K including what type of food? 16. Eggs A) Dairy products B) Citrus fruits C) Green leafy vegetables D) Ans: D Feedback: Injectable vitamin K is used to reverse the effects of warfarin. Vitamin K is responsible for promoting the liver synthesis of several clotting factors. When these pathways have been inhibited by warfarin, clotting time is increased. If an increased level of vitamin K is provided, more of these factors are produced, and the clotting time can be brought back within a normal range. Green leafy vegetables are high in vitamin K and should be avoided or minimized in the diet to prevent reversal of warfarin effects. The other food options are not high in vitamin K. The nurse evaluates teaching about warfarin (Coumadin) is successful when the patient makes what statement? 17. If I miss a dose, I will take two pills the next day. A) I will check with the pharmacist before taking any herbal supplements. B) I will increase the dark-green leafy vegetables in my diet. C) I will take a multivitamin daily. D) Ans: B Feedback: Warfarin is involved in many drugdrug  and drugherb  interactions so the patients statement about checking with the doctor before starting any new drugs or supplements would be correct. The other statements made by the patient indicate the need for further teaching because he or she should not take two pills after missing a dose, there is no need to increase green leafy vegetables containing vitamin K, and multivitamin use is contraindicated.