CH 48 Coagulation PREPU

A patient is discharged from the hospital with a prescription of warfarin (Coumadin). Which of the following statements indicates successful patient teaching?

"I will avoid herbal remedies." Rationale: Most commonly used herbs and supplements have a profound effect on drugs for anticoagulation. The patient should never double up on dosing related to a missed dose. The patient should avoid green leafy vegetables due to vitamin K. The patient should not take a multivitamin.

Which of the following is classified as an antiplatelet agent? (Choose one)

Clopidogrel (Plavix) Rationale: Plavix is an antiplatelet agent. Activase is a thrombolytic agent. Mephyton is an anticoagulant antagonist. Coumadin is an oral anticoagulant. Lovenox is a parenteral anticoagulant.

Fondaparinux (Arixtra) is indicated for which of the following? (Choose one)

DVT prophylaxis Rationale: Fondaparinux (Arixtra) is indicated for DVT prophylaxis.

The client is prescribed warfarin. His INR is 5.2. At what level is this dose?

Elevated Rationale: Warfarin dosage is regulated according to the INR (derived from the prothrombin [PT] time), for which a therapeutic value is between 2.0 to 3.0 in most conditions. A therapeutic PT value is approximately 1.5 times the control, or 18 seconds.

Regular use of antiplatelet medications can contribute to increased risk of bleeding. Your patient, a 79-year-old woman, is admitted to the hospital with black, tarry stools and several large, scattered ecchymosis. She has a history of TIAs and has taken clopidogrel for several years. What would you expect the physician to prescribe to control her bleeding?

None of these. Rationale: Clopidogrel irreversibly blocks the (ADP) receptor on platelet cell membranes. This effectively prevents platelet aggregation for the lifespan of the platelet. Platelet transfusion should be considered in patients who take these drugs and develop bleeding complications.

Which of the following would be considered a topical hemostatic agent?

Thrombin Rationale: Thrombin is a topical hemostatic agent. Protamine sulfate is the antidote for heparin. Pentoxifylline is a hemorrheologic agent (one that can induce hemorrhage). Urokinase is a thrombolytic agent.

A male patient is receiving heparin by continuous intravenous infusion. The nurse will instruct the patient and family members to report which of the following should it occur?

Presence of blood in urine or stools Rationale: The nurse should instruct the patient and family members to report the presence of blood in urine or stools and any bleeding from the gums, nose, vagina, or wounds. The anticoagulation properties of heparin can sometimes result in abnormal bleeding. Sleepiness, drowsiness, skin rash, and dizziness are not commonly identified adverse effects of the drug.

Warfarin typically takes 3 days to achieve its onset of action.

True Rationale: Warfarin's onset of action is about 3 days; its effects last for 4 to 5 days.

While preparing a patient for discharge, you teach her about the proper use of warfarin, which has been prescribed by the physician. Which of the following statements by the patient indicates that additional teaching is required?

"I should use aspirin to control my arthritis pain." Rationale: Aspirin is an antiplatelet agent that can increase the effect of warfarin. Patients taking warfarin should check with a health care professional before taking any analgesic. The other statements suggest that the client understands important aspects of warfarin therapy.

A patient is receiving low-molecular-weight heparin to prevent thromboembolic complications. The nursing student asks her instructor the reason why this treatment is given instead of heparin. What is the instructor's best explanation of the rationale for LMWH over heparin?

"LMWH is associated with less thrombocytopenia than standard heparin." Rationale: Low-molecular-weight heparins are associated with less thrombocytopenia than standard heparin. Low-molecular-weight heparin is not stronger than standard heparin. Low-molecular-weight heparin is administered cautiously in patients with blood dyscrasia and hypertension.

A patient is being administered heparin IV and has been started on warfarin (Coumadin). The patient asks the nurse why she is taking both medications. What is the nurse's most accurate response?

"Warfarin takes 3-5 days to develop anticoagulant effects, and you still need heparin." Rationale: Anticoagulant effects do not occur for 3-5 days after warfarin is started because clotting factors already in the blood follow their normal pathway of elimination. The statement "After a certain period of time, you must start warfarin and heparin together" does not explain clearly the reason for the two medications concurrently. The statement "You will need both warfarin and heparin for several days" does not explain clearly the reason for the two medications. The statement "Warfarin cannot be given without heparin due to the amount of clotting you need" is not accurate.

A client is started on enoxaparin immediately after hip surgery. The nurse would explain to the client that this drug will be continued for how long?

7 to 10 days Rationale: When used for hip surgery, enoxaparin typically is administered for 7 to 10 days to prevent deep vein thrombosis that may lead to pulmonary embolism after hip replacement.

A nurse will use extreme caution when administering heparin to which of the following patients?

A 38-year-old male with peptic ulcer disease Rationale: Heparin should be administered with extreme caution to patients with peptic ulcer or liver disease or after surgery because those patients would have greater risk for hemorrhage or excessive blood loss. Urticaria is a listed adverse effect of taking heparin and would therefore be expected. A patient who takes heparin would be advised to not drink heavily or smoke, but neither would have the safety risk posed by a patient with peptic ulcer. A patient with an accelerated heart rate and on heparin therapy would be at no special risk.

Heparin therapy is prescribed to a patient with deep vein thrombosis. Which patient would be at greatest risk of bleeding from this therapy?

A 45-year-old corporate executive with peptic ulcer disease Rationale: Heparin is also contraindicated in patients with thrombocytopenia, bleeding disorders, and active bleeding other than DIC. This drug should be used with caution in patients with the potential for hemorrhage (e.g., immediately after surgery, with peptic ulcer disease, and with liver disease).

The client is diagnosed with chronic renal insufficiency. Her vascular access site becomes incompetent, and the physician orders urokinase to dissolve the clot. What should the nurse do?

Administer the drug as ordered. Rationale: Most anticoagulant, antiplatelet, and thrombolytic drugs may be used in clients with impaired renal function. For example, heparin and warfarin may be used in usual dosages, and thrombolytic agents (e.g., streptokinase, urokinase) may be used to dissolve clots in IV catheters or vascular access sites for hemodialysis. (less)

A patient has been administered heparin to prevent thromboembolism development status postmyocardial infarction. The patient develops heparin-induced thrombocytopenia. Which of the following medications will be administered?

Argatroban (Acova) Rationale: Heparin-induced thrombocytopenia may occur in 1-3% of those receiving heparin and is a very serious side effect of heparin. In this patient all heparin administration must be discontinued and anticoagulation managed with a direct thrombin inhibitor, such as argatroban. The patient is not administered vitamin K, calcium gluconate, or aminocaproic acid.

A 61-year-old man is prescribed alteplase for an acute myocardial infarction. A priority nursing intervention will be to monitor for which of the following during and after drug therapy?

Arrhythmias Rationale: A patient who is on alteplase therapy to treat a myocardial infarction should be monitored for arrhythmias using a cardiac monitor. Reperfusion arrhythmias are common when blood flow to the heart has been reestablished. The patient's blood pressure should also be monitored but would not be the priority intervention. Gastrointestinal distress and liver failure are not associated with alteplase therapy.

A nurse is caring for a patient receiving the anticoagulant drug warfarin. What pre-administration assessments should the nurse perform before administering the drug to the patient?

Assess prothrombin time (PT) and INR. Rationale: The nurse should assess the prothrombin time (PT) and INR before administering the anticoagulant drug warfarin to the patient. Observing for signs of thrombus formation, assessing for signs of bleeding, and monitoring for hypersensitivity reaction are the ongoing assessments performed in patients who are administered warfarin.

A 60-year-old patient experienced a sudden onset of chest pain and shortness of breath and was subsequently diagnosed with a pulmonary embolism in the emergency department. The patient has been started on an intravenous heparin infusion. How does this drug achieve therapeutic effect?

By inactivating clotting factors and thus stopping the coagulation cascade Rationale: Heparin, along with antithrombin, rapidly promotes the inactivation of factor X, which, in turn, prevents the conversion of prothrombin to thrombin. Heparin does not achieve its therapeutic effect through the excretion or inhibition of vitamin K or by inhibiting platelet aggregation.

A nurse would anticipate the need for an increased dosage of warfarin if the patient was also receiving which of the following?

Carbamazepine Rationale: Carbamazepine decreases the anticoagulant effects of warfarin necessitating an increased dose of warfarin. Clofibrate increases the bleeding effects of warfarin necessitating a decreased dosage of warfarin. Amiodarone increases the bleeding effects of warfarin necessitating a decreased dosage of warfarin. Danazol increases the bleeding effects of warfarin necessitating a decreased dosage of warfarin.

Which agent would a nurse expect to administer to a patient with Christmas disease?

Factor IX complex Rationale: Factor IX complex is used to treat hemophilia B, also known as Christmas disease. Antihemophilic factor is used to treat hemophilia A. Aminocaproic acid is used to treat excessive bleeding in hyperfibrinolytic states. Vitamin K would be used to treat an overdose of warfarin.

The most common adverse effects associated with antiplatelet agents are headache and dizziness.

False Rationale: Increased bruising and bleeding from the gums while brushing the teeth are the most common adverse effects associated with antiplatelet agents.

A nurse is caring for a patient receiving heparin therapy. The nurse instructs the patient and family that certain foods must be taken in limited quantity as they interfere with the effect of the therapy. Which of the following foods must be taken in limited quantity?

Foods rich in vitamin K Rationale: The nurse should inform the patient to limit the intake of foods rich in vitamin K as they interfere with the heparin therapy. Foods rich in vitamin A, C, or D need not be taken in limitation, as they do not affect the treatment.

A patient has developed the formation of clots and has bruising. It is determined that there is a depletion of coagulation factors and widespread bleeding. Which of the following medications will be administered?

Heparin Rationale: The development of clots and widespread bleeding is indicative of disseminated intravascular coagulation. The patient should be administered heparin to slow the formation of clots. The goal of heparin therapy in DIC is to prevent blood coagulation long enough for clotting factors to replenish and control hemorrhage. Aminocaproic acid is used to control excessive bleeding from systemic hyperfibrinolysis. Warfarin is administered orally to decrease clot formation. Protamine sulfate would not be administered.

Ms. Adams is started on warfarin therapy. The patient asks you why she is not on heparin therapy any longer. What differentiates heparin from warfarin?

Heparin is administered parenterally, while warfarin is administered orally. Rationale: Heparin is administered parenterally, while warfarin is administered orally. Warfarin is administered after heparin therapy to complete treating a thrombus or embolism. Patients receiving heparin therapy will begin taking warfarin before they discontinue heparin. This overlap allows the warfarin to reach a therapeutic level before heparin is discontinued. However, both the drugs are used to treat thrombosis and thromboembolic disorders and have equally serious adverse effects, such as bleeding. Anticoagulants, such as warfarin and heparin, prevent new clot formation or extension of an existing clot, while thrombolytics dissolve existing blood clots.

Mr. Hon has been admitted to the hospital and placed on anticoagulant therapy. For what blood-related disorder is this therapy used?

Hypercoagulation Rationale: Anticoagulants are used to treat hypercoagulation, or excessive coagulation. They prevent the blood from clotting unexpectedly and maintain the flow of blood. Hemophilia is treated with human factor IX complex. Blood cancer is treated with therapies such as chemotherapy or radiation treatment. On the other hand, hemostasis is the process by which the body prevents excessive blood flow during an injury.

A 59-year-old patient is on warfarin therapy. On follow-up visits to the clinic, the nurse will assess the patient for which of the following?

Intake of vitamin K Rationale: It is important to assess the patient's usual vitamin K intake because warfarin interferes with the synthesis of vitamin K-derived clotting factors. Increases in vitamin K intake will interfere with the action of warfarin if the increase in intake occurs after the warfarin dosage has been titrated. In addition, a deficiency of vitamin K can increase the risk of bleeding. The patient's sugar intake or the presence of a skin-related or breathing disorder does not affect the administration of warfarin.

A 59-year-old client with vascular disorders is prescribed cilostazol. The nurse instructs the client that it is for the treatment of what condition?

Intermittent claudication Rationale: This drug is intended for the treatment of intermittent claudication, which is an arterial disorder. Pulmonary embolism, deep-vein thrombosis, and venous stasis are all venous disorders.

A 75-year-old client presents to the physician's office with bleeding gums and multiple bruises. When the nurse reviews the client's drug history, the nurse finds that he is prescribed aspirin 81 mg/d. What drug may cause increased bleeding when used in conjunction with the aspirin?

NSAIDs Rationale: NSAIDs, which are commonly used by older adults, also have antiplatelet effects. Clients who take an NSAID daily may not need low-dose aspirin for antithrombotic effects.

A client is to receive clopidogrel. The nurse would expect to administer this agent by which route?

Oral Rationale: Clopidogrel is administered orally.

A client is receiving warfarin. The nurse would expect to administer this drug by which route?

Oral Rationale: Warfarin is administered orally.

What values are used to monitor the effectiveness of warfarin therapy?

PT and INR Rationale: Warfarin dose is regulated according to the international normalized ratio (INR), which is based on prothrombin time (PT). PT and INR are assessed daily until a stable daily dose is reached. Thereafter, PT and INR are determined every few weeks for the duration of warfarin therapy.

After reviewing the drugs that may interfere with warfarin, the students indicate that they need additional study when they identify which of the following as requiring a dosage increase in the warfarin?

Phenytoin Rationale: When combined with phenytoin, warfarin leads to a decrease in anticoagulant effect, which would necessitate an increase in the dosage of the warfarin. Clofibrate, quinidine, and cefoxitin increase the risk of bleeding with warfarin; thus, a decreased dose of warfarin would be indicated.

Which of the following is used to treat a warfarin (Coumadin) overdose? (Choose one)

Phytonadione Rationale: Phytonadione (vitamin K) is indicated for the treatment of warfarin overdose.

The client is admitted to the hospital after a suicide attempt. The nurse discovers that the client overdosed on aspirin. What does the nurse expect the physician to do?

Prescribe a transfusion of platelets. Rationale: No antidote exists for the effects of aspirin or the adenosine diphosphate receptor antagonists, because both produce irreversible platelet effects; platelet transfusion may be required.

The physician discovers a clot in the client's left lower leg. The physician prescribes anticoagulant drugs to prevent formation of new clots and to achieve which other effect?

Prevent extension of clots already present Rationale: Anticoagulant drugs are given to prevent formation of new clots and extension of clots already present.

A nurse is caring for a 64-year-old female patient who is receiving IV heparin and reports bleeding from her gums. The nurse checks the patient's laboratory test results and finds that she has a very high aPTT. The nurse anticipates that which of the following drugs may be ordered?

Protamine sulfate Rationale: If a patient who receives IV heparin is found to be highly anticoagulated, protamine sulfate may be prescribed. Protamine sulfate, which is a strong base, reacts with heparin, which is a strong acid, to form a stable salt, thereby neutralizing the anticoagulant effects of heparin. Protamine sulfate does not produce the same effects for coumadin, alteplase, or ticlopidine.

A client exhibits signs and symptoms of heparin overdose. The nurse would anticipate administering which of the following?

Protamine sulfate Rationale: Protamine sulfate is the antidote for heparin overdose. Vitamin K is the antidote for warfarin overdose. Urokinase is a thrombolytic. Drotrecogin alfa is a C reactive protein that has anticoagulant effects.

Enoxaparin (Lovenox) should be administered via which route? (Choose one)

Subcutaneous injection Rationale: Enoxaparin (Lovenox) is administered via subcutaneous injection.

Ms. Main is sent home with subcutaneous heparin after a total hip replacement. What symptom would indicate a serious drug reaction?

Tarry stools Rationale: Tarry stools would be an indication of gastrointestinal bleeds. The most common adverse effect of heparin is bleeding.

A stable daily dose of warfarin is reached when which parameter is achieved?

The PT and INR are within their therapeutic ranges, and the dose does not cause bleeding. Rationale: When warfarin is started, PT and INR should be assessed daily until a stable daily dose is reached (the dose that maintains PT and INR within therapeutic ranges and does not cause bleeding).

The squad just delivered to your ED a 73-year-old man with crushing chest pain. He has a history of cardiovascular disease. Onset of symptoms is within the last 60 minutes. What medication would you expect the physician to order for his thromboembolic disorder?

Thrombolytic drugs Rationale: The main use of thrombolytic agents is for management of acute, severe thromboembolic disease, such as myocardial infarction or pulmonary embolism.

Heparin is the anticoagulant of choice during lactation.

True Rationale: Although some adverse fetal affects 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.

You are caring for a 73-year-old client receiving warfarin. When you perform your initial shift assessment, you observe blood in the client's urinary drainage bag. After reporting your observation to the physician, which of the following substances will you likely administer?

Vitamin K Rationale: Genitourinary bleeding is an adverse effect of warfarin. Vitamin K, a hemostatic agent that controls bleeding caused by warfarin overdose, will likely be administered to this patient.

A patient who is receiving warfarin (Coumadin) has blood in his urinary drainage bag. What medication will likely be ordered by the physician?

Vitamin K Rationale: Vitamin K is the antidote for warfarin overdose. Aminocaproic acid is used to control excessive bleeding from systemic hyperfibrinolysis. Platelets are a blood product, not a medication. Protamine sulfate is the antidote for heparin therapy.

A nurse has an order to administer heparin. Before initiating this therapy, a priority nursing assessment will be the patient's

aPTT. Rationale: Before initiating therapy, it is important to review the patient's aPTT, hematocrit, and platelet count. These tests provide baseline information on the patient's blood clotting abilities and identify conditions that may cause heparin therapy to be contraindicated. The patient's heart rate and pulse, electrolyte levels, and blood sugar levels would not be priority nursing assessments.

The physician orders heparin for a 35-year-old female client. The nurse administers the drug only after confirming that the client

does not have peptic ulcer disease. Rationale: Contraindications of heparin include GI ulcerations (e.g., peptic ulcer disease, ulcerative colitis), active bleeding, severe kidney or liver disease, severe hypertension, and recent surgery of the eye, spinal cord, or brain. The drug should be used cautiously in patients with non-severe hypertension.

You are caring for a 76-year-old client who is receiving IV heparin 5000 units q4h. At the initiation of therapy, the patient's control activated thromboplastin time (aPTT) was found to be 35 seconds. One hour prior to the next scheduled dose, aPTT is determined to be 92 seconds. Based on this result, you will

hold the dose and contact the physician. Rationale: During heparin therapy, aPTT values are typically maintained between 1.5 to 2.5 times the control value. Since an aPTT value of 92 seconds is greater than 2.5 times this patient's control value, the anticoagulation effect is too great, and the physician should be notified.

The pharmacology instructor is discussing clopidogrel. According to the instructor, this drug is frequently used for

reduction of myocardial infarction in patients with atherosclerosis. Rationale: Clopidogrel is indicated for reduction of myocardial infarction, stroke, and vascular death in patients with atherosclerosis.

Which of the following are examples of low-molecular-weight heparins (LMWHs)? Select all that apply:

• Dalteparin (Fragmin) • Enoxaparin (Lovenox) • Tinzaparin (Innohep) Rationale: Dalteparin, enoxaparin, and tinzaparin are all examples of LMWHs.

After teaching a group of students about anticoagulants, the instructor determines that the teaching was successful when the students identify which of the following agents as interacting with warfarin that increases the risk of bleeding? Select all that apply.

• Salicylates • Ranitidine • Metronidazole • Cefoxitin Rationale: Salicylates, ranitidine, metronidazole, and cefoxitin interact with warfarin resulting in the increased risk of bleeding. Barbiturates and carbamazepine interact with warfarin resulting in a decreased anticoagulant effect.