Transcript Pharmacology and the Nursing Process, 4th ed. Lilley/Harrington

Chapter 26
Coagulation Modifier Drugs
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Hemostasis
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General term for any process that stops bleeding
Coagulation is hemostasis that occurs due to
physiologic clotting of blood
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
Antifibrinolytic or hemostatic
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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 (cont’d)
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warfarin sodium (Coumadin)
enoxaparin (Lovenox)
heparin
dabigatran (Pradaxa)
fondaparinux (Arixtra)
argatroban (Argatroban)
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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
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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
May also cause:
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Heparin-induced thrombocytopenia (HIT)
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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Classroom Response Question
A patient is receiving an IV infusion of heparin and was
started on warfarin therapy the night before. Which statement
is most correct?
A. The patient is receiving a double dose of anticoagulants.
B. The heparin therapy was ineffective, so the warfarin was
started.
C. The heparin provides anticoagulation until therapeutic
levels of warfarin are reached.
D. The heparin and warfarin work together synergistically to
provide anticoagulation.
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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
 Do NOT rub after administration
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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 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
clopidogrel (Plavix)
• prasugrel (Effient) and ticagrelor (BRILINTA) are similar to
clopidogrel
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tirofiban (Aggrastat), eptifibatide (Integrilin),
abciximab (ReoPro)
• 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
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Vary according to drug
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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
Current drugs
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anistreplase (Eminase)
 alteplase (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
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Nausea, vomiting, hypotension, anaphylactoid
reactions
Cardiac dysrhythmias; can be dangerous
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Classroom Response Question
A patient is receiving an intravenous infusion of a thrombolytic
drug during treatment for an acute MI. The nurse notices that
there is a slight amount of bleeding from the antecubital area
where venous lab work was drawn. What will the nurse do
first?
A. Monitor the site for further bleeding.
B. Apply pressure to the site with a gauze pad.
C. Slow the rate of infusion of the thrombolytic drug.
D. Stop the infusion of the thrombolytic drug.
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Antifibrinolytic Drugs
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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
Treatment of hemophilia or von Willebrand’s
disease
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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:
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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Nursing Implications
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Assess:
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Patient history, medication history, allergies
 Contraindications
 Baseline vital signs, laboratory values
 Potential drug interactions
 History of abnormal bleeding conditions
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Heparin: Nursing Implications
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Intravenous doses are usually double-checked
with another nurse
Ensure that subcutaneous doses are given
subcutaneously, not IM
Subcutaneous 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 subcutaneous doses within 2 inches
of:
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The umbilicus, abdominal incisions, or open wounds,
scars, drainage tubes, stomas
Do not aspirate subcutaneous injections or
massage injection site
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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 (Coumadin):
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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Classroom Response Question
A 75-year-old man fell at home and hit his head against a table. His wife
reports to their daughter that he does not have cuts or scratches, but
there is a small lump on his upper scalp. She does not see any blood. He
is taking warfarin and an antidysrhythmic as part of his treatment for
chronic atrial fibrillation. What is the main concern at this time?
A. Pressure should be applied to the lump for 3 to 5 minutes.
B. He will need to take two doses of warfarin tonight to prevent blood
clotting.
C. He needs to be examined for possible internal bleeding from the fall.
D. As long as there is no bleeding, there is no concern.
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Warfarin (Coumadin):
Nursing Implications
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Many herbal products have potential
interactions—increased bleeding may occur
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Capsicum pepper
 Garlic
 Ginger
 Ginkgo
 St. John’s wort
 Feverfew
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Classroom Response Question
A 72-year-old woman is taking an over-the-counter multivitamin
that contains ginkgo. Her physician has recommended that she
start taking low-dose aspirin therapy as part of her treatment for
transient ischemic attacks (TIAs). The concern with taking these
two drugs together is:
A. increased risk of gastric ulcer.
B. decreased action of the aspirin because of the interaction with
the ginkgo.
C. increased risk of bleeding because of the ginkgo.
D. antagonism of the action of the aspirin because of the
multivitamins.
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Anticoagulants:
Patient Education
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Education should include:
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Importance of regular laboratory testing
Signs of abnormal bleeding
Measures to prevent bruising, bleeding, or tissue
injury
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Anticoagulants:
Patient Education (cont’d)
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Education should include (cont’d):
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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
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Antiplatelet Drugs:
Nursing Implications
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Concerns and teaching tips same as for
anticoagulants
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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