Coagulation Modifier Drugs Flashcards
Hemostasis
General term for any process that stops bleeding
Coagulation
Is hemostasis that occurs because of the physiological 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
Coagulation System
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
Fibrinolytic System
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
Fibrin in the clot binds to a circulating protein known as?
Fibrin in the clot binds to a circulating protein known as plasminogen. This binding converts plasminogen to plasmin.
Plasmin
Plasmin is the enzymatic protein that eventually breaks down the fibrin thrombus into fibrin degradation products. This keeps the thrombus localized to prevent it from becoming an embolus.
Hemophilia
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.
Hemophilia
Two types inhibit platelet aggregation
Factor VII deficiency
Factor VIII deficiency or factor IX deficiency, or both
Five Coagulation Modifier Drugs
Anticoagulants
Antiplatelet drugs
Hemorheological drugs
Thrombolytic drugs
Antifibrinolytic or hemostatic
Anticoagulants
Prevent clot formation/prevent formation of clotting factors
Antiplatelet drugs
Inhibit platelet aggregation
Prevent platelet plugs
Hemorheological drugs
Alter platelet function without preventing the platelets from working
Thrombolytic drugs
Lyse (break down) existing clots
Antifibrinolytic or hemostatic
Promote blood coagulation
Anticoagulants
Also known as?
No direct effect on?
Prevents?
Also known as antithrombotic drugs
Have no direct effect on a blood clot that is already formed
Prevent intravascular thrombosis by decreasing blood coagulability
Anticoagulants are used prophylactically to prevent (2)
Clot formation (thrombus)
An embolus (dislodged clot)
If an embolus lodges in a coronary artery, it causes?
If it obstructs a brain vessel, it causes?
If it travels to the lungs, it is a?
If it travels to a vein in the leg, it is a?
Collectively, these complications are called “__________________.”
myocardial infarction
a stroke (a cerebrovascular accident).
pulmonary embolus.
deep vein thrombosis (DVT).
thromboembolic events
Anticoagulants
Heparin:
Mechanism of action
Factors? are?
Action: inhibit clotting factors IIa (thrombin), Xa, and IX
Factors XI and XII are also inactivated but do not play as important of a role as the other three factors.
Anticoagulants
Heparin: Types and 2 important medication
Unfractionated heparin: “heparin”
Low-molecular-weight heparins
enoxaparin (Lovenox)
Other Low molecular: dalteparin (Fragmin)
nadroparin calcium (Fraxiparine)
tinzaparin sodium (Innohep).
Heparins
Unfractionated heparin (heparin)
Relatively large molecule that is derived from animal sources
Frequent laboratory monitoring for bleeding times such as aPTT
Heparin for catheter flush (10-100 units/mL): no monitoring is needed
Heparins
LMWHs/ Low-molecular-weight heparins
Synthetic smaller molecular structure
More predictable anticoagulant response
Frequent laboratory monitoring of bleeding times using tests such as aPTT not needed
Anticoagulant: Heparin Indications
Prevent clot formation for circumstance that may lead to stroke, heart attack, pulmonary embolism, DVT
Also used (both heparin & LMWs) as bridge therapy when a patient stops warfarin for surgery or other invasive procedures
Anticoagulants
Warfarin (Coumadin)
Inhibits vitamin K synthesis by bacteria in the gastrointestinal tract
Action: inhibit vitamin K–dependent clotting factors II, VII, IX, and X which are normally synthesized in the liver
Final effect is the prevention of clot formation
Anticoagulants
Antithrombin medication
2 types and 1 important medication
Action: inhibit thrombin (factor IIa)
Natural
—human antithrombin III (Thrombate)
Synthetic
—-dabigatran (Pradaxa)
lepirudin (Refludan)
argatroban (Argatroban)
bivalirudin (Angiomax)
Anticoagulants
Direct acting Xa inhibitors:
Action:
1 medication
Action: inhibit factor
rivaroxaban (Xarelto)
Other:
fondaparinux (Arixtra)
apixaban (Eliquis)
Anticoagulants
Direct thrombin inhibitor
dabigatran
Anticoagulants:Mechanism of Action
Vary, depending on drug
Work on different points of the clotting cascade
Prevent intravascular thrombosis by decreasing blood coagulability
Do not lyse existing clots
Anticoagulants: Indications
Used to prevent clot formation in certain settings in which clot formation is likely:
-Myocardial infarction
-Unstable angina
-Atrial fibrillation
-Indwelling devices, such as mechanical heart valves
-Conditions in which blood flow may be slowed and blood may pool (e.g., major orthopedic surgery, prolonged periods of immobility)
Anticoagulants: Contraindications
Drug allergy
Any acute bleeding process or high risk of such an occurrence
Warfarin is strongly contraindicated in pregnancy.
Other anticoagulants are rated in lower pregnancy categories.
Low-molecular-weight heparins are contraindicated in patients with an indwelling epidural catheter risk of epidural hematoma
Anticoagulants: Adverse Effects
Bleeding
Risk increases with increased dosages
May be localized or systemic
Anticoagulants may also cause:
Heparin-induced thrombocytopenia
Nausea, vomiting, abdominal cramps, thrombocytopenia, other effects
Warfarin adverse effects
Bleeding
Lethargy
Muscle pain
Skin necrosis
“Purple toes” syndrome
Heparin-Induced Thrombocytopenia Type 1
Gradual reduction in platelets
Heparin therapy can generally be continued.
Heparin-Induced Thrombocytopenia Type 2
Acute fall in the number of platelets (more than 50% reduction from baseline)
Discontinue heparin therapy.
Heparin-Induced Thrombocytopenia
Treatment
Thrombosis that can be fatal
Treatment: thrombin inhibitors bivalirudin and argatroban
Incidence ranges from 5 to 15% of patients.
Higher with bovine than with porcine heparins
Toxic Effects of Heparin
Treatment
Aimed at reversing the underlying cause
Stop drug immediately.
Intravenous (IV) protamine sulphate: 1 mg of protamine can reverse the effects of 100 units of heparin (1 mg of protamine for each milligram of low-molecular-weight heparin given).
Symptoms of toxic effects of Heparin
hematuria, melena (blood in the stool), petechiae, ecchymoses, and gum or mucous membrane bleeding
Treatment: Toxic Effects of Warfarin (4)
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 (10 mg) of vitamin K given intravenously will reverse the anticoagulation within 6 hours.
Treatment: Toxic Effects of Warfarin
When vitamin K is given, warfarin resistance will occur for up to?
Can cause?
IV vitamin K has risk of? how to prevent it?
Common to give the injectable form?
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
Intravenous vitamin K: risk of anaphylaxis. Risk is diminished by diluting it and giving it over 30 minutes.
Common to give the injectable form orally.
Drug Interactions: Anticoagulants
Interactions are profound and complicated.
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 intestine
Alteration in the platelet count or activity
Heparin sodium is obtained from?
Natural anticoagulant obtained from the lungs or intestinal mucosa of pigs
Heparin sodium
Dosage
DVT prophylaxis
Do we monitor for phrophylaxis?
Protocol
10 to 10 000 units/mL
DVT prophylaxis: 5 000 units subcutaneously two or three times a day. Does not need to be monitored when used for prophylaxis.
Weight-based protocol
What to test for when heparin is used therapeutically (for treatment/ continuous IV infusion?
Measurement of activated partial thromboplastin time (aPTT) (usually every 6 hours until therapeutic effects are seen) is necessary.
Heparin Flushes
Name of heparin
Risk of the development of?_____has caused most institutions to use 0.9% normal saline as a flush for heparin-lock IV ports.
Heparin flushes (100 units/mL) are still used for?
Heparin Leo
Small vial of aqueous heparin IV flush solution
Risk of the development of heparin-induced thrombocytopenia has caused most institutions to use 0.9% normal saline as a flush for heparin-lock IV ports.
Heparin flushes (100 units/mL) are still used for central catheters.
Warfarin sodium
Most commonly prescribed oral anticoagulant
What to monitor for warfarin?
Normal INR
Therapeutic INR with warfarin?
Careful monitoring of the prothrombin time(PT)/international normalized ratio (INR)
A normal INR (without warfarin) is 0.8 to 1.2
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).
Warfarin sodium considerations
Dietary considerations
Variations in certain genes (CYP2CP and VKORC1)
Age considerations
Maintenance dose determined by the INR
Natural health product cautions
Direct Thrombin Inhibitors 1 medication
Dabigitran etexilate mesylate (Pradaxa)
Dabigitran etexilate mesylate (Pradaxa)
First oral direct thrombin inhibitor approved for stroke and thrombosis prevention in patients with atrial fibrillation
Prodrug that needs liver activation, extensively excreted by kidneys
No antidote with most serious adverse effect of bleeding
No coagulation monitoring necessary
Antiplatelet Drugs
Prevent platelet adhesion
Platelet function: forms a clot to stop bleeding
Antiplatelet Drugs 3 medications
aspirin
clopidogrel bisulfate (Plavix)
eptifibatide (Integrilin)
Others:
prasugrel (Effient)
treprostinil (Remodulin)
abciximab (ReoPro)
tirofiban (Aggrastat)
anagrelide hydrochloride (Agrylin)
dipyridamole (Aggrenox, Persantine)
Antiplatelets Drugs
Aspirin
Inhibits?
Results?
Affects?
Used for?
Inhibits cyclooxygenase in the platelet which prevents TXA2 (TXA2 causes platelet aggregation and vasoconstriction)
Resultant effect of vasodilation, and prevention of platelet aggregation and clot formation
May affect vitamin K dependent clotting factors
Used for stroke prevention (you have seen low dose therapy of 81mg ECASA daily)
Antiplatelets: Clopidogrel (Plavix)
Most commonly used?
Alters?
Better than?
Used for?
Most commonly used ADP (adenosine diphosphate) inhibitor
Alters platelet membrane so that it can no longer receive signal to aggregate and form plug
Shown to be better than aspirin at reducing number of MI’s, strokes and vascular deaths for at-risk patients
Used for above issues plus preventing TIAs and post MI thrombotic prevention
Antiplatelets
Eptifibatide (Integrilin)
Type?
Used in?
Route?
Blocks?
Treats?
GP II/IIIa inhibitor
Used in critical care or cardiac catheterization laboratory settings where continuous cardiac monitoring is available
IV only
Block the receptor protein in the platelet membrane
Treat acute unstable angina, MI and during PCI (pericoronary interventions such as angioplasty)
Antiplatelet Drugs: Indications and Adverse Effects
Antithrombotic effects; Adverse effects (prevent clot formation)
Can be serious, as they pose a risk for inducing bleeding.
Vary according to drug
Thrombolytic Drugs
Drugs that break down, or lyse, existing clots in the coronary arteries
Thrombolytic Drugs
2 Current drugs
Older drugs
streptokinase and urokinase
Current drugs
alteplase (Activase)
tenecteplase (TNKase)
Thrombolytic Drugs: Mechanism of Action
Activate the fibrinolytic system to break down the clot in the blood vessel quickly
Activate plasminogen and convert it to plasmin, which lyses the thrombus
Plasmin is a proteolytic enzyme.
Mimics the body’s own process of clot destruction
Plasmin
is a proteolytic enzyme.
Thrombolytic Drugs: Indications (6)
Acute myocardial infarction
Arterial thrombolysis
DVT
Occlusion of shunts or catheters
Pulmonary embolism
Acute ischemic stroke
Thrombolytic Drugs: Adverse Effects
Bleeding
-Internal
-Intracranial
-Superficial
Other effects
-Nausea, vomiting, hypotension, hypersensitivity, anaphylactoid reactions
-Cardiac dysrhythmias; can be dangerous
Antifibrinolytic Drugs
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 A or type I von Willebrand’s disease with desmopressin
Antifibrinolytic Drugs
1 medication
desmopressin acetate (DDAVP)
Others:
aprotinin (Artiss, Trasylol)
tranexamic acid (Cyklokapron)
desmopressin acetate (DDAVP)
Used in?
Which disease is it most commonly used in?
Is it commonly used today?
In extreme circumstances may be used for surgical and postoperative hemostasis
May be used to stop bleeding in patients with hemophilia A or type 1 von Willebrand’s disease
Not as commonly used today
Antifibrinolytic Drugs:Adverse Effects
Uncommon and mild
Rare reports of thrombotic events
Others include:
Dysrhythmia, orthostatic hypotension, bradycardia, headache, dizziness, fatigue, hallucinations, convulsions, nausea, vomiting, abdominal cramps, diarrhea
Nursing Implications
Assess
-Patient history, medication history, allergies
-Contraindications
-Baseline vital signs, laboratory values
-Potential drug interactions
-History of abnormal bleeding conditions
Heparin: Nursing Implications
Intravenous doses are usually double-checked with another nurse.
Ensure that subcutaneous doses are given subcutaneously, not intramuscularly.
Subcutaneous doses should be given in areas of deep subcutaneous fat, and sites should be rotated.
IV doses may be given by bolus or IV infusions.
Anticoagulant effects are seen immediately.
2 DO NOT DO’s for Heparin
Do not give subcutaneous doses within 5 cm of the umbilicus, abdominal incisions, open wounds, scars, drainage tubes, stomas, or areas of bruising or oozing.
Do not aspirate subcutaneous injections or massage the injection site.
-May cause hematoma formation
Lab values for Heparin? and frequency?
Antidote?
Laboratory values are done daily to monitor coagulation effects (aPTT).
Protamine sulphate can be given as an antidote in case of excessive anticoagulation.
Low-Molecular-Weight Heparins: Nursing Implications
Route
Antidote
Given subcutaneously in the abdomen
Rotate injection sites.
Protamine sulphate can be given as an antidote in case of excessive anticoagulation.
[HP- printer]
Warfarin (Coumadin):Nursing Implications
May be started while the patient is on? until?
Onset
Labs?
Antidote?
May be started while the patient is still on heparin until PT/INR levels indicate adequate anticoagulation
Full therapeutic effect takes several days.
Monitor PT/INR regularly; keep follow-up appointments.
Antidote is vitamin K. [W is near x in the alphabet]
Many herbal products have potential interactions with WARFARIN
Name 6
Effects?
Capsicum pepper
Garlic
Ginger
Ginkgo
St. John’s wort
Feverfew
increased bleeding may occur
Anticoagulants:Patient Education
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 the physician before taking other drugs or over-the-counter products, including herbals
Food people taking anticoagulants should avoid
Avoiding foods high in vitamin K (tomatoes, dark leafy green vegetables)
Antiplatelet Drugs:Nursing Implications
Importance of regular laboratory testing
Signs of abnormal bleeding
Measures to prevent bruising, bleeding, and tissue injury
Drug–drug interactions
Adverse reactions to report
Thrombolytic Drugs:Nursing Implications
Follow strict manufacturer’s guidelines for preparation and administration.
Monitor IV sites for bleeding, redness, and pain.
Monitor for bleeding from gums, mucous membranes, nose, and injection sites.
Watch for signs of internal bleeding (decreased blood pressure, restlessness, increased pulse).
Signs of internal bleeding
decreased blood pressure, restlessness, increased pulse
