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Anticoagulants
- Not blood thinners!
- General use: prevention & treatment of thromboembolic disorders including DVTs, pulmonary embolism, & atrial fibrillation with embolization. Also used in management of MI sequentially or in combination with thrombolytics and/or antiplatelet agents.
- Used to prevent clot formation
- They Do Not dissolve clots
- Monitor pt for signs of bleeding, PT-INR, aPTT
- Avoid alcohol and NSAIDS
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Heparin
- Accelerates the rate that antithrombin III neutralizes thrombin and factor x
- Low dose- prevents conversion of prothrombin to thrombin
- High dose- prevents conversion of fibrinogen to fibrin
- Monitor aPTT (activated partial thromboplastin time) goal is 1 1/2 to 2 x control/normal
- Given IV or SQ (IV immediate onset short half life, SQ rapid onset 20-60min, given in abd
- IV dose based on APTT resulst q6 hours till stable then daily (weight based nomograms allow nurse to adjust dose based on pt weight and APTT result)
- SQ low dose, q8-12 hours, less monitoring required
- Adverse effect: GI/GU bleed
- High alert medication verify dose with 2nd nurse
- D/C 12-24 hours before surgery
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Protamins Sulfate
- Neutralizes heparin activity
- Given for life threatening hemorrhage
- Slow IV infusion
- Risk of anaphylaxis
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HIT
Heparin Induced Thrombocytopenia
- White clot syndrome
- Monitor platelet counts
- Immune reaction to heparin
- D/D heparin if thrombocytomenia (platelet drop by 50%)
- Onset usually 5-22 days on heparin (o.5% pf pts)
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Enoxaparin (Lovenox)
Low Molecular Weight Heparin
less effect on thrombin, allows SQ admin based on weight w/o lab monitoring - used to prevent DVT
- Adverse: bleeding, thrombocytopenia, elevated AST, ALT
- Monitorplatelet and report drop in platelet count
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Lepirudan (refludan)
- Parenteral anticoagulant
- direct thrombin inhibitor
- used for pts with HIT
- IV dosing- monitor APTT
- caution w/renal insufficiency
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Coumadin (warfarin)
- Interferes with hepatic synthesis of vitamin K dependent clotting factors (II, VII, IX, X)
- inhibits thrombus formation & extension
- Prolongs prothrombin time & APTT
- 72 hours or more to reach adequate anticoagulation
- 2-7 days to stabilize
- May overlap therapy w/heparin
- PO primarily--IV rarely
- Reduce risk of stroke or MI
- Adverse: bleeding, usually due to OD, rare GI upset (n/v/d, cramps), elevate liver function tests
- Caution with other drugs causing bleeding: aspirin, NSAIDSa, ETOH, corticosteroids, other anticoagulants
- Antibiotics decrease bacterial activity in gut; decrease synthesis of vitamin K; increase coumadin effect (prolong prothrombin time)
- Nursing Implications: monitor prothrombin time, want 1 1/2 to 2 x control; INR goal is 2.0--3.0Diet caution vitamin K intake
- Monitor for bleedingNo meds w/o dr approval
- No IM injections
- Not safe in pregnancyD/C 4-7 days before surgery based on INR
- Keep app for lab workVITAMIN K- reversal agent when INR >5PO for INR 5-8; IV infuse vitamin K for INR >8
- risk of anaphylaxis greater w/IV- reserve for hemorrhage & INR>8
- Severe bleeding give fresh frozen plasma to restore clotting factors
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Abciximab (reopro)
- Platelet Aggregation InhibitorBlocks platelet aggregation
- Inhibits binding of fibrinogen to platelets
- Given IV after MI, angioplasty, or stent placement to prevent occlusion
- Adverse: rash, GI upset, bleeding disorder
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Clopidogrel (plavix)
- Platelet Aggregation Inhibitor
- Antiplatelet agent
- Less toxicity, leukopenia, thrombocytopenia
- Interaction: clopidogrel & omeprazole - increased mortality
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Platelet Aggregation Inhibitor
- Blocks platelet aggregation
- Inhibits binding of fibrinogen to platelets
- Prolongs bleeding time
- Used to prevent MI or stroke
- Adverse: rash, GI upset, bleeding disorders
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Pradaxa (dabigatran etexilate)
- Inhibits thrombin
- Used to prevent stroke & clots in pts with Afib
- Compare w/coumadin- pts had fewer strokes
- Blood level monitoring not necessary
- Adverse: bleeding
- GI symptoms- dyspepsia, pain, nausea, heartburn, bloating
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Acetylsalicylic Acid (Aspirin)
- In platelets blocks production of thromboxane A2- an inducer of platelet aggregation. Since platelets don't synthesize, action on platelets is permanent (life span of platelet 7-10 days)
- Repeated doses have cumulative effect
- Doses 80-160 mg/day
- More effective given BID in diabetics
- Prevent stroke & MI in high risk pt
- Adverse: allergy, bleeding (especially GI)
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Fibrinolytic Agents
Clot Busters
- Tissue Plasminogen Activators
- Plasminogen when activated becomes a protease- binds to fibrin- fibrinolysis
- tPA activates bound plasminogen vs free; targets clots
- Hepatically metabolized
- Short half life
- Given IV bolus, then infusion over 1 hour
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tPA (alteplase, activase)
- Recombinant variations of tPA- reteplase & tenecteplase
- Longer half lifes- give in 2 IV boluses
- Similar efficacy & toxicity
- Use: Thrombolysis in MI, CVA, pulmonary embolus
- Risk: bleeding. Usually given w/ASA, heparin
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Contraindications of tPA
- Risk of Bleeding1- surgery w/in 10 days, trauma, CPR2- GI bleed w/in 3 months3- Hypertension, uncontrolled (diastolic >110)
- 4- Active bleeding or hemorrhagic disorder
- 5- Previous CVA or acute intracranial process
- 6- Aortic dissection
- 7- Acute pericarditis
- Administer IV in ICU or ER w/cardiac monitoring
- Observe for s/s bleeding- GI,GU,IV sites, risk of CVA
- Observe for therapeutic response; MI- ekg changes, CVA- recovery of neuro function, pulmonary embolism- improved oxygenation
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