Transcript Chapter_28
CHAPTER 28
Coagulation Modifier Drugs
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Hemostasis
The process that halts bleeding after injury to
a blood vessel
Complex relationship between substances
that promote clot formation and either inhibit
coagulation or dissolve a formed clot
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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
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Coagulation Modifier Drugs
Anticoagulants
Inhibit the action or formation of clotting factors
Prevent clot formation
Antiplatelet drugs
Inhibit platelet aggregation
Prevent platelet plugs
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Coagulation Modifier Drugs
(cont’d)
Hemorheologic drugs
Thrombolytic drugs
Alter platelet function
Lyse (break down) existing clots
Hemostatic or antifibrinolytic drugs
Promote blood coagulation
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Anticoagulants
Also known as antithrombotic drugs
Have no direct effect on a blood clot that is
already formed
Used prophylactically to prevent
Clot formation (thrombus)
An embolus (dislodged clot)
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Anticoagulants:
Mechanism of Action
Vary, depending on drug
Work on different points of the clotting
cascade
Do not lyse existing clots
Heparin and low–molecular-weight heparins
Turn off coagulation pathway and prevent clot
formation
warfarin (Coumadin)
fondaparinux (Arixtra)
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Anticoagulants:
Mechanism of Action (cont’d)
All ultimately prevent clot formation
Heparin
Low–molecular-weight heparins
warfarin (Coumadin)
fondaparinux (Arixtra)
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Anticoagulants (cont’d)
Prevention of clot formation also prevents:
Stroke
Myocardial infarction (MI)
Deep vein thrombosis (DVT)
Pulmonary embolism (PE)
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Anticoagulants: Indications
Used to prevent clot formation in certain
settings where clot formation is likely
Myocardial infarction
Unstable angina
Atrial fibrillation
Indwelling devices, such as mechanical heart
valves
Major orthopedic surgery
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Anticoagulants:
Adverse Effects
Bleeding
Risk increases with increased dosages
May be localized or systemic
Heparin-induced thrombocytopenia (HIT)
May also cause:
Nausea, vomiting, abdominal cramps,
thrombocytopenia, others
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Anticoagulants (cont’d)
Heparin
Monitored by activated partial thromboplastin
times (aPTTs)
Parenteral
Short half-life (1 to 2 hours)
Effects reversed by protamine sulfate
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Anticoagulants (cont’d)
Low–molecular-weight heparins
enoxaparin (Lovenox) and dalteparin (Fragmin)
More predictable anticoagulant response
Do not require laboratory monitoring
Given subcutaneously
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Anticoagulants (cont’d)
warfarin sodium (Coumadin)
Given orally only
Monitored by prothrombin time (PT) and INR
(PT-INR)
Vitamin K can be given if toxicity occurs
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Antiplatelet Drugs
Prevent platelet adhesion
aspirin
dipyridamole (Persantine)
clopidogrel (Plavix) and ticlopidine (Ticlid)
• ADP inhibitors
tirofiban (Aggrastat), eptifibatide (Integrilin),
abciximab (ReoPro)
• New class, GP IIb/IIIa inhibitors
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Antiplatelet Drugs: Indications
Antithrombotic effects
Reduce risk of fatal and nonfatal strokes
Acute unstable angina and MI
Adverse effects
Vary according to drug
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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
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Antifibrinolytic Drugs (cont’d)
aminocaproic acid (Amicar)
desmopressin (DDAVP)
Similar to ADH
Also used in the treatment of diabetes insipidus
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Antifibrinolytic Drugs:
Indications
Prevention and treatment of excessive
bleeding
Hyperfibrinolysis
Surgical complications
Excessive oozing from surgical sites such as
chest tubes
Reducing total blood loss and duration of bleeding
in the postoperative period
Treatment of hemophilia or von Willebrand’s
disease
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Antifibrinolytic Drugs:
Adverse Effects
Uncommon and mild
Rare reports of thrombotic events
Others include:
Dysrhythmia, orthostatic hypotension,
bradycardia, headache, dizziness, fatigue,
nausea, vomiting, abdominal cramps, diarrhea,
others
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Thrombolytic Drugs
Drugs that break down, or lyse, preformed
clots
Older drugs
streptokinase and urokinase
Newer drugs
Tissue plasminogen activator (t-PA)
Anisoylated plasminogen-streptokinase activator
complex (APSAC)
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Thrombolytic Drugs (cont’d)
anistreplase (Eminase)
alteplase (t-PA, Activase)
reteplase (Retavase)
tenecteplase (TNKase)
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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 can digest fibrin
Reestablish blood flow to the heart muscle
via coronary arteries, preventing tissue
destruction
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Thrombolytic Drugs:
Indications
Acute MI
Arterial thrombolysis
DVT
Occlusion of shunts or catheters
Pulmonary embolus
Acute ischemic stroke
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Thrombolytic Drugs:
Adverse Effects
Bleeding
Internal
Intracranial
Superficial
Other effects
Nausea, vomiting, hypotension, anaphylactoid
reactions
Cardiac dysrhythmias; can be dangerous
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Nursing Implications
Assess:
Patient history, medication history, allergies
Contraindications
Baseline vital signs, laboratory values
Potential drug interactions—there are MANY!
History of abnormal bleeding conditions
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Heparin: Nursing Implications
Intravenous doses are usually doublechecked with another nurse
Ensure that SC doses are given SC, not IM
SC doses should be given in areas of deep
subcutaneous fat, and sites rotated
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Heparin: Nursing Implications
(cont’d)
Do not give SC doses within 2 inches of:
The umbilicus, abdominal incisions, or open
wounds, scars, drainage tubes, stomas
Do not aspirate SC injections or massage
injection site
May cause hematoma formation
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Heparin: Nursing Implications
(cont’d)
IV doses may be given by bolus or IV
infusions
Anticoagulant effects seen immediately
Laboratory values done daily to monitor
coagulation effects (aPTT)
Protamine sulfate can be given as an antidote
in case of excessive anticoagulation
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LWMHs: Nursing Implications
Given subcutaneously in the abdomen
Rotate injection sites
Protamine sulfate can be given as an antidote
in case of excessive anticoagulation
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Warfarin Sodium:
Nursing Implications
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
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Warfarin:
Nursing Implications
Many herbal products have potential
interactions—increased bleeding may occur
Capsicum pepper
Garlic
Ginger
Gingko
Ginseng
Feverfew
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Anticoagulants:
Patient Education
Education should include:
Importance of regular lab testing
Signs of abnormal bleeding
Measures to prevent bruising, bleeding, or
tissue injury
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Anticoagulants:
Patient Education (cont’d)
Education should include (cont’d):
Wearing a medical alert bracelet
Avoiding foods high in vitamin K (tomatoes,
dark leafy green vegetables)
Consulting physician before taking other
meds or over-the-counter products, including
herbals
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Antiplatelet Drugs:
Nursing Implications
Concerns and teaching tips same as for
anticoagulants
Dipyridamole should be taken on an empty
stomach
Drug-drug interactions
Adverse reactions to report
Monitoring for abnormal bleeding
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Thrombolytic Drugs:
Nursing Implications
Follow strict manufacturer’s guidelines for
preparation and administration
Monitor IV sites for bleeding, redness, pain
Monitor for bleeding from gums, mucous
membranes, nose, injection sites
Observe for signs of internal bleeding
(decreased BP, restlessness, increased
pulse)
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Coagulation Modifier Drugs:
Nursing Implications
Monitor for therapeutic effects
Monitor for signs of excessive bleeding
Bleeding of gums while brushing teeth,
unexplained nosebleeds, heavier menstrual
bleeding, bloody or tarry stools, bloody urine or
sputum, abdominal pain, vomiting blood
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Coagulation Modifier Drugs:
Nursing Implications (cont’d)
Monitor for adverse effects
Increased BP, headache, hematoma formation,
hemorrhage, shortness of breath, chills, fever
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