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
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“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
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Anticoagulants
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Inhibit the action or formation of clotting factors
Prevent clot formation
Antiplatelet drugs
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Inhibit platelet aggregation
Prevent platelet plugs
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Coagulation Modifier Drugs
(cont’d)
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Hemorheologic drugs
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Thrombolytic drugs
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Alter platelet function
Lyse (break down) existing clots
Hemostatic or antifibrinolytic drugs

Promote blood coagulation
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Anticoagulants
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Also known as antithrombotic drugs
Have no direct effect on a blood clot that is
already formed
Used prophylactically to prevent

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Clot formation (thrombus)
An embolus (dislodged clot)
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Anticoagulants:
Mechanism of Action
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Vary, depending on drug
Work on different points of the clotting
cascade
Do not lyse existing clots
Heparin and low–molecular-weight heparins
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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)
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Prevention of clot formation also prevents:
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Stroke
Myocardial infarction (MI)
Deep vein thrombosis (DVT)
Pulmonary embolism (PE)
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Anticoagulants: Indications
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Used to prevent clot formation in certain
settings where clot formation is likely
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Myocardial infarction
Unstable angina
Atrial fibrillation
Indwelling devices, such as mechanical heart
valves
Major orthopedic surgery
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Anticoagulants:
Adverse Effects
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Bleeding
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
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)
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Heparin
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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)
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Low–molecular-weight heparins
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enoxaparin (Lovenox) and dalteparin (Fragmin)
More predictable anticoagulant response
Do not require laboratory monitoring
Given subcutaneously
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Anticoagulants (cont’d)
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warfarin sodium (Coumadin)
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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
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Prevent platelet adhesion
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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
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Antithrombotic effects
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Reduce risk of fatal and nonfatal strokes
Acute unstable angina and MI
Adverse effects

Vary according to drug
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Antifibrinolytic Drugs
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
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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)
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
aminocaproic acid (Amicar)
desmopressin (DDAVP)
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Similar to ADH
Also used in the treatment of diabetes insipidus
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Antifibrinolytic Drugs:
Indications
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Prevention and treatment of excessive
bleeding
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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
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Uncommon and mild
Rare reports of thrombotic events
Others include:
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Dysrhythmia, orthostatic hypotension,
bradycardia, headache, dizziness, fatigue,
nausea, vomiting, abdominal cramps, diarrhea,
others
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Thrombolytic Drugs
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Drugs that break down, or lyse, preformed
clots
Older drugs
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
streptokinase and urokinase
Newer drugs


Tissue plasminogen activator (t-PA)
Anisoylated plasminogen-streptokinase activator
complex (APSAC)
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Thrombolytic Drugs (cont’d)
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anistreplase (Eminase)
alteplase (t-PA, Activase)
reteplase (Retavase)
tenecteplase (TNKase)
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Thrombolytic Drugs:
Mechanism of Action
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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
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Acute MI
Arterial thrombolysis
DVT
Occlusion of shunts or catheters
Pulmonary embolus
Acute ischemic stroke
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Thrombolytic Drugs:
Adverse Effects
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Bleeding
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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
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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)
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Do not give SC doses within 2 inches of:
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
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)
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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
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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
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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
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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
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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
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
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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