Chap 26 Coagulation Modifier Drugs

Question 1

Hemostasis

Answer 1

General term for any process that stops bleeding
Coagulation is hemostasis that occurs because of the physiologic clotting of blood.
Complex relationship between substances that promote clot formation and either inhibit coagulation or dissolve a formed clot
Thrombus*: technical term for a *blood clot *
Embolus: thrombus that moves through blood vessels

Question 2

Embolus

Answer 2

Thromboembolic events
Myocardial infarction (MI): embolus lodges in a coronary artery
Stroke:* embolus obstructs a brain vessel
Pulmonary emboli:* embolus in the pulmonary circulation
Deep vein thrombosis (DVT): embolus goes to a vein in the leg

Question 3

Coagulation System

Answer 3

Cascade”
Each activated factor serves as a catalyst that amplifies the next reaction.
Result is fibrin, a clot-forming substance.
Intrinsic pathway and extrinsic pathway

Question 4

Fibrinolytic System

Answer 4

Initiates the breakdown of clots and serves to balance the clotting process
Fibrinolysis*: mechanism by which formed thrombi are lysed to prevent excessive clot formation and blood vessel blockage

Question 5

Hemophilia

Answer 5

Rare genetic disorder
Natural coagulation and hemostasis factors are limited or absent.
Patients with hemophilia can bleed to death if coagulation factors are not given.
Two types inhibit platelet aggregation
Factor VII deficiency
Factor VIII and/or factor IX deficiency

Question 6

Coagulation Modifier Drugs

Answer 6

Anticoagulants
Inhibit the action or formation of clotting factors
Prevent clot formation
Antiplatelet drugs
Inhibit platelet aggregation
Prevent platelet plugs

Hemorheologic drugs
Alter platelet function without preventing the platelets from working
Thrombolytic drugs
Lyse (break down) existing clots
Antifibrinolytic or hemostatic
Promote blood coagulation

Question 7

Anticoagulants

Answer 7

Also known as antithrombotic drugs
Have no direct effect on a blood clot that is already formed
Prevent intravascular thrombosis by decreasing blood coagulability
Used prophylactically to prevent
Clot formation (thrombus)*
An embolus (dislodged clot)*

Heparins
Action: inhibit clotting factors IIa (thrombin) and Xa
Unfractionated heparin: “heparin”
Lo–molecular-weight heparins (LMWHs)
Enoxaparin (Lovenox)
Dalteparin (Fragmin)

Question 8

Anticoagulant
Heparin

Answer 8

Natural anticoagulant obtained from the lungs or intestinal mucosa of pigs
10 to 40,000 units/mL
DVT prophylaxis: 5000 units subcutaneously two or three times a day; does not need to be monitored when used for prophylaxis
When heparin is used therapeutically (for treatment), continuous IV infusion.
Measurement of aPTT (usually every 6 hours until therapeutic effects are seen) is necessary.
Heparin for catheter flush (10 to 100 units/mL): no monitoring is needed**

Low Molecular Weight Heparin
Pre-filled syringes
Do not expel air bubble**

Question 9

Anticoagulant
Enoxaparin (Lovenox)

Answer 9

Prototypical LMWH
Greater affinity for factor Xa than for factor Iia
Higher degree of bioavailability and longer elimination half-life
Lab monitoring is not necessary.
Injectable form
Used for prophylaxis and treatment
Pre-filled syringes**
Do not expel air bubble**

Question 10

Treatment: Toxic Effects of Heparin

Answer 10

Symptoms: hematuria* melena (blood in the stool), petechiae, ecchymoses, and gum or mucous membrane bleeding
Stop* drug immediately.*
Intravenous (IV) protamine sulfate: 1 mg of protamine can reverse the effects of 100 units of heparin.

Question 11

Anticoagulant
Coumarins

Answer 11

Action: inhibit vitamin K–dependent clotting factors II, VII, IX, and X
Warfarin (Coumadin)
Warfarin (Coumadin)**
Most commonly prescribed oral anticoagulant
Inhibits vitamin K synthesis by bacteria in the gastrointestinal tract
Inhibits production of vitamin K–dependent clotting factors II, VII, IX, and X, which are normally synthesized in the liver
Final effect prevention of clot formation
Careful monitoring of the prothrombin time/international normalized ratio (PT/INR)
A normal INR (without warfarin) is 1.0, but a therapeutic INR (with warfarin) ranges from 2 to 3.5, depending on the indication for use of the drug (e.g., atrial fibrillation, thromboprevention, prosthetic heart valve).
Variations in certain genes, CYP2CP and VKORC1
Many drug interactions
Dietary considerations

Question 12

Treatment:
Toxic Effects of Warfarin

Answer 12

Discontinue the warfarin.**
May take 36 to 42 hours before the liver can resynthesize enough clotting factors to reverse the warfarin effects
Vitamin K1 (phytonadione) can hasten the return to normal coagulation.
High doses of *vitamin K (10 mg) given IV will reverse the anticoagulation within 6 hours.**

Caution: when vitamin K is given, warfarin resistance will occur for up to 7 days.
Severe bleeding: transfusions of human plasma or clotting factor concentrates.
Life-threatening bleeding from warfarin: Kcentra and Profiline
IV vitamin K: risk of anaphylaxis. Risk is diminished by diluting it and giving it over 30 minutes.

Question 13

Anticoagulants: Factor Xa Drugs**

Answer 13

Fondaparinux (Arixtra)
Rivaroxaban (Xarelto)
Apixaban (Eliquis)
Edoxaban (Savaysa)
Betrixaban (Bevyxxa)
Inhibits thrombosis by its specific action against factor Xa

Question 14

Anticoagulant
Fondaparinux (Arixtra)

Answer 14

Selective inhibitor of factor Xa
Prophylaxis or treatment of DVT or PE**
Bleeding* is most common* and serious* adverse reaction.*
Anemia, wound drainage, hematoma, confusion, UTI, hypotension, dizziness, hypokalemia
Thrombocytopenia can occur
Should not be given for at least 6 to 8 hours after surgery
Use withcaution with warfarin
Subcutaneous injections

Question 15

Anticoagulant
Rivaroxaban (Xarelto)*

Answer 15

First oral factor Xa inhibitor
Used for prevention of strokes in patients with a-fib; post-op thromboprophylaxis with ortho surgeries; treatment of DVT and PE
Adverse reactions: Peripheral edema, dizziness, headache, bruising, diarrhea, hematuria, and bleeding

Question 16

Anticoagulants Direct Thrombin Inhibitors

Answer 16

Action: inhibit thrombin (factor IIa)
Human antithrombin III (Thrombate)
Lepirudin (Refludan)
Argatroban (Argatroban)
Bivalirudin (Angiomax)
Dabigatran (Pradaxa)

Question 17

Argatroban

Answer 17

Synthetic direct thrombin inhibitor
Used for active HIT and percutaneous coronary intervention procedures in patients at risk for HIT
Only given IV

Question 17

Dabigatran (Pradaxa)

Answer 17

First oral direct thrombin inhibitor that is approved for prevention of strokes and thrombosis in patients with nonvalvular atrial fibrillation
Prodrug that becomes activated in the liver
Specifically, and reversibly binds to both free and clot-bound thrombin
Dose dependent on renal function
Adverse effects: bleeding, GI bleeding
No coagulation monitoring is required.

Question 18

Idarucizumab (Praxbind)*

Answer 18

Specific dabigatran antidote**
Reverses the anticoagulant effects for dabigatran for emergency surgery or in life-threatening or uncontrolled bleeding

Question 19

Anticoagulants: Contraindications

Answer 19

Drug allergy
Any acute bleeding process or high risk for such an occurrence.
Warfarin* is strongly *contraindicated in pregnancy.**
Other anticoagulants are rated in lower pregnancy categories (B or C).
LMWHs are contraindicated in patients with an indwelling epidural catheter risk of epidural hematoma.

Question 20

Anticoagulants: Adverse Effects

Answer 20

Bleeding**
Risk increases with increased dosages.
May be localized or systemic
May also cause:
Heparin-induced thrombocytopenia**
Nausea, vomiting, abdominal cramps, thrombocytopenia, others

Question 21

Drug Interactions: Anticoagulants**

Answer 21

Enzyme inhibition of metabolism
Displacement of the drug from inactive protein-binding sites
Decrease in vitamin K absorption or synthesis by the bacterial flora of the large intestines
Alteration in the platelet count or activity

Question 21

Antiplatelet Drugs

Answer 21

Work to prevent platelet adhesion at the site of blood vessel injury
Platelets normally flow through blood vessels without adhering to their surfaces
Collagen from damaged vessels stimulate platelet adhesion

Prevent platelet adhesion
Aspirin*
Cilostazol (Pletal)
Clopidogrel (Plavix)*
Prasugrel (Effient)*
Treprostinil (Remodulin)
Abciximab (ReoPro)*
Eptifibatide (Integrilin)*
Tirofiban (Aggrastat)*
Anagrelide (Agrylin)
Dipyridamole (Persantine)*

Question 22

Aspirin

Answer 22

Available in many combinations with other prescription and nonprescription drugs
Contraindicated for flulike symptoms in children and teenagers
Reye’s syndrome**
Aspirin and dipyridamole (Aggrenox)
Used for antiplatelet purposes

Question 23

Clopidogrel (Plavix)**

Answer 23

Most widely used ADP inhibitor
Oral use
Prasugrel (Effient), ticagrelor (Brilinta)
Similar to clopidogrel
Many drug interactions

Question 24

Thrombolytic* Drugs

Answer 24

Drugs that break down, or lyse, preformed clots
Older drugs
Streptokinase and urokinase
Current drugs
Alteplase* (Activase, Cathflo Activase)
Reteplase* (Retavase)
Tenecteplase *(TNKase)

Question 25

Thrombolytic Drugs: 
Mechanism of Action

Answer 25

Activate the fibrinolytic system to break down the clot in the blood vessel quickly
Activate plasminogen and convert it to plasmin, which can digest fibrin
Reestablish blood flow to the heart muscle via coronary arteries, preventing tissue destruction

Question 26

Thrombolytic Drugs: 
Adverse Effects

Answer 26

Bleeding
Internal
Intracranial
Superficial
Other effects
Nausea, vomiting, hypotension, anaphylactoid reactions
Cardiac dysrhythmias; can be dangerous

Question 27

Alteplase (Activase)**

Answer 27

t-PA made through recombinant DNA techniques
Fibrin specific so does not produce a systemic lytic state
Present in the body in a natural state
Very short half-life (5 minutes)
Indications: MI, strokes
Smaller doses to flush clogged IV or arterial lines

Question 28

Antifibrinolytic* Drugs

Answer 28

Prevent the lysis of fibrin**
Result in promoting clot formation
Used for prevention and treatment of excessive bleeding resulting from hyperfibrinolysis or surgical complications
Treatment of hemophilia or von Willebrand’s disease**
AmTranexamic acid (Cyklokapron)
Desmopressin
inocaproic acid (Amicar)

Question 29

Antifibrinolytic Drugs:
Adverse Effects

Answer 29

Uncommon and mild
Rare reports of thrombotic events
Others include
Dysrhythmia, orthostatic hypotension, bradycardia, headache, dizziness, fatigue, nausea, vomiting, abdominal cramps, diarrhea, others

Question 30

Desmopressin (DDAVP)

Answer 30

Synthetic polypeptide
Similar to vasopressin, which is an antidiuretic hormone
Indications: diabetes insipidus; hemophilia
*Nasal spray: used for nocturnal enuresis **

Question 31

Nursing Implications

Answer 31

Assess
Patient history, medication history, allergies
Contraindications**
Baseline vital signs, laboratory values**
Potential drug interactions **
History of abnormal bleeding conditions**

Question 32

Heparin: Nursing Implications

Answer 32

Do not give subcutaneous doses within 
2 inches of:
The umbilicus, abdominal incisions, open wounds, scars, drainage tubes, or stomas
Do not aspirate subcutaneous injections or massage the injection site**
May cause hematoma formation**

Question 32

Warfarin (Coumadin):
Nursing Implications

Answer 32

Many herbal products have potential interactions; increased bleeding may occur
Capsicum pepper
Garlic*
Ginger*
Ginkgo*
St. John’s wort*
Feverfew

Question 33

Anticoagulants:
Patient Education

Answer 33

Education should include:
Importance of regular laboratory testing
Signs of abnormal bleeding**
Measures to prevent bruising, bleeding, and tissue injury**
Wearing a medical alert bracelet**
Avoiding foods high in vitamin K (tomatoes, dark leafy green vegetables)**
*Consulting physician before taking other drugs** or over-the-counter products, including herbals