Upgrade to remove ads
Only $35.99/year

Coagulation DO Drugs

Terms in this set (62)

Hemostasis
The stopping of blood flow (clotting). The physiological process of hemostasis must maintain a delicate balance between blood fluidity and coagulation.
Hemostasis: Stage 1
Blood vessel injury, vessel spasms and constricts, blood flow, platelets become sticky and adhere to each other and vessel. ADP, thrombin, thromboxane A2 facilitate aggregation. Platelet plug formation begins when platelets come into contact with collagen at site of damage. Glycoprotein & von Willebrand's factor make adhesion possible. More platelets are attracted to area. Blood flow decreased, formation of an insoluble clot occurs
Hemostasis: Stage 2
Production of fibrin (protein) that reinforces platelet plug. The clotting cascade begins when clotting factors VIII, IX, X, IXa) convert to their active forms (VIIIa, IXa). Fibrin threads create a mesh net that traps blood constituents to form a clot.
Intrinsic pathway
Activated in response to injury
Extrinsic pathway
Activated in response to blood leakage from a vessel entering tissue.
What happens near end of clotting cascade?
Prothrombinase is formed and converts prothrombin to thrombin. Thrombin converts fibrinogen to fibrin (long strands). Fibrin forms the frame for the clot. Thrombin and fibrin form after injury.
How long does it take to form a clot?
About 6 minutes.
What role does the liver pay in formation of a clot?
Several clotting factors, including fibrinogen, are proteins made by the liver. Liver needs vitamin K to make clotting factors. If you have liver problems you will have coagulation problems.
Blood Clot removal
Fibrinolysis (clot removal) begins 24-48 hrs, continues as long as needed. TPA (tissue plasminogen activator) secreted by nearby blood vessel cells. TPA converts plasminogen to plasmin. Plasmin digests fibrin strands to remove clot.
Thrombolytic Disorders
Body forms undesirable clots which may grow too large (thrombus) with too much fibrin.
Arterial thrombi cause what?
Reduced blood flow, MI, CVA
What is a traveling clot called?
Embolus
Atrial fibrillation can cause what?
Emboli from right: PE
Emboli from left: CVA or other arterial infarction.
Who is vulnerable for an embolus?
Abdominal surgery, anigography, heart valve disease, arterial catheters, travelers.
Thrombocytopenia
Platelet deficiency from bone marrow suppression; usually from immunosupressant/chemo drugs
Hemophilia A
Genetic.
Deficiency Factor VIII, 80%
Hemophilia B
Genetic.
Deficiency factor IX, 20%
Treatment for hemophilia
Administer clotting factor, fresh frozen plasma
Von Willenbrand's disease
Decreased quantity/quality platelet aggregation; vW factor.
Tx: Factor VIII & desmopressin (DDAVP) (releases stored vW factor)
What to anticoagulants do?
Inhibit specific clotting factors to prevent clot formation.
What to antiplatelets do?
Inhibit platelet action
What do thrombolytics do?
Drugs that dissolve clot.
What do hemostatic drugs do?
Promotes clot formation; inhibits fibrin destruction.
Anticoagulants
"Blood thinners" (don't really thin blood). Increases clotting time and prevents thrombi forming/growing in VEINS by either inhibiting a clotting factor or diminish clotting of platelets. Imparts negative charge to platelet surface which inhibits "clumping", platelet aggregation.
Start IV/SQ then PO.
Heparin.
Enhances action of antithrombin III which inactivates thrombin and inhibits coagulation.
Loss of clotting factor prevents fibrin clot formation. Only suppresses formation of further fibrin and eventually clots. Acts quickly to bind with antithrombin III and therefore results happen quickly. Half life ~1.5 hrs (IV/SQ). Oral anticoagulants might take days to begin working
HIT
Heparin induced thrombocytopenia. 5-10 days, leads to increased thromboembolism.
Low-molecular-weight heparins
Enoxaprin (Lovenox), Dalteparin (Fragmin), Tinzaparin (Imnohep).
Similar to heparin but more specific to Factor X.
2-4x longer duration, more stable, fewer labs.
Can give SQ at home when labs are stable.
Less likely to cause thrombocytopenia
Excess bleeding still a threat: monitor gums, urine.
Monitor DVT s/s (calf edema, warmth, pain w/dorsiflexion)
Direct Thrombin Inhibitors
Parenteral (Minor),
Lepirudin (Refludan), argatroban(Novastan)
Prevent/treat thrombocytopenia from heparin tx
Bivalirudin (Angiomax)
Direct Thrombin Inhibitor. Given wtih ASA before angiopalsty to prevent thrombi; SE back pain.
Desirudin (Iprivask)
15 minutes before hip surgery to prevent DVT.
Antithrombin (Atryn)
From genetically engineered goat for hereditary antithrombin deficient patients.
Warfarin (Coumadin)
PO anitcoagulant. Inhibits hepatic synthesis of coag factors II, VII, IX, X and prothrombin.
Antidote to Coumadin is VitK.
Often start heparin and transition to warfarin with 2-3 day overlap.
Coumadin will not work on existing clotting factors, must wait till clotting factors dissipate (6hrs-2.5 days)
May take 8-12 hrs to reach therapeutic effects and effects may be seen for 2-5 days after d/c
Drug of Choice for long-term suppression of clotting.
Warnings with Coumadin
Many meds interfere with Coumadin, so don't take anything else!
Need consistent Vit K intake: don't eat large amounts of green leafy veg, green tea, cranberry juice, ETOH.
Pregnancy category X
Antidotes
Heparin: Protamine sulfate
Warfarin: Vitamin K
Use antidotes when adverse effects of bleeding are present, especially after trauma/surgery.
What labs to we look at for Heparin?
aPTT: activated partial thromboplasin time.
Should be 1.5-2x control (normal value: 25-35 seconds)
What labs do we look at for Warfarin?
PT/INR: Prothrombin time
INR should be 2-3.
Alternative PO anticoagulants
NO ANTIDOTE!
Xarelto, Eliquis, Pradaxa
Warning: anticoagulants use with caution in pts with high likelihood of profuse bleeding.
Hemophilia
Increased capillary permeability
Dissecting aneurysm
Peptic ulcer disease
Severe HTN
Spontaneously threatening abortion
Severe renal/kidney/liver disease
Reasons to use anticoagulants
PE
Antigoaculate usage for pregnancy
DVT (heparin/Coumadin used mainly for venous thrombi)
Open heart surgery
renal dialysis
Post-op for DVT prevention
DIC
AMI: prophylactic and current Tx
Stroke: prophylactic and current Tx
Se/AR for anticoagulants
Hemorrhage
HIT (decreased platelet count)
Hypersensitivity rxns (w/heparin, made from animal tissue)
Osteoporosis (long term usage)
Lab test for Coumadin (Warfarin)
INR should be 2-3 in most; may be 3-4.5 in others.
May take a week or longer for INR to ajdust to correct range after dosage has been adjusted.
What labs do we look at for Heparin?
Ongoing monitoring of aPTT
Normal 40 seconds
Therapeutic: 1.5-2x normal or 60-80seconds
Anticoagulant patient teaching
SCDs
Antiembolic stockings(TED hose)
Travel: exercises, walking, avoid prolonged sitting, fluids, support hose.
S/S increased bleeding (epitaxis, hematuria, black/tarry stools, pallor, tachycardia, oozing blood)
Report new s/s
Limit ETOH
soft toothbrush, electric razor
no contact sports
no aspiration of heparin, no massage.
What do antiplatelet meds do? What do we use them for?
Suppress platelet aggregation. Used to suppress clots in ARTERIES. Platelet cores are the bulk of arterial thrombus. Used to prevent thromboembolic events in pts with recent history of MI, stroke or PAD (peripheral artery disease). Also for thrombi prophylaxis in pt with unstable angina. May be given off label to prevent postop DVTs. Usually given for those who can't tolerate aspirin.
Antiplatelet: Aspirin
Supresses platelet aggregation by causing irreversible inhibition of cyclooxygenase (Cox 1&2).
Primarily used as prophylaxis for AMI
Low dose ('baby") dosage of 81mg usually sufficient.
Upt o 325 mg can be used (maybe use enteric-coated to prevent probs)
Antiplatelet meds: ADP agonists (PO)
Causes irreversible blockage of ADP receptors on the platelet surface and prevent aggregation.
Clopidogrel (Plavix): generally well tolerated, expensive. Use if can't take aspirin; flu-like s/s: HA, dizziness, rash.
Taking with PPI (proton pump inhibitors; Prilosec) increases risk MI; AR: bleeding.
Ticlopidine (Ticlid): not as safe, blood dyscrasis
Similar precautions as ASA.
Antiplatelets: Glycoprotein GP IIb/IIIa receptor antagonists
"Super aspirins"
Most effective anti-platelet drugs. All administered IV, usually in combo with ASA and low-dose heparin.
Very expensive
Used short-term to prevent ischemic events in pts w/ acute coronary syndrome (ACS) and those undergoing PTCA.
Other random antiplatelet drugs
Abciximaab (ReoPro)
Eptifibatide (Integrelin)
Tirofiban (Aggrastat)
Strong contraindications for antiplatelet meds
Recent of active internal bleeding
History of recent CVA
Intracranial or intraspinal surgery
Trauma w/i past 2 months
Intracranial neoplasm
Arterovenous malformation
Aneurysm
Known coagulation disorder
Severe, uncontrolled HTN
What is the difference between an anticoagulant and an antiplatelet?
Antiplatelet drugs prevents clot formation in the arteries. Anticoagulants are primarily used to prevent thrombosis in veins.
Penoxyfylline (Trental)
Antiplatelet med used to reduce RBC viscosity
For intermitent claudication (pain in leg muscles r/t peripheral arterial disease (atherosclerosis)
Not a great drug
Thrombolytic meds
Designed to break apart existing clots. Dissolves insoluble fibrin.
Uses: AMI, PE, ISCHEMIC CVA, DVT
Give within 4 hrs.
Monitor VS & bleeding/bruising
Action stops with IV cessation.
Four main thrombolytic meds
Streptokinase (from animal product and can exhibit allergic rxn)
Tenecteplase (TNKase); faster onset and longer duration
Rereplase (Retavase); recombinant DNA (used off label to celar thrombosed central lines)
tPA (Alteplase): synthetic so no allertic rxns, much more expensive. (clear thrombosed CL)
Relative contraindication for Thrombolytic therapy
Major surgery within last 10 days
Cerebrovascular disease
GI or GU bleeding w/i last 10 day
Recent trauma (CPR w/i 10 days)
HTN with SBP above 180mm and/or DBP above 110
Likelihood of left heart thrombus
Subacute bacterial endocarditis
Acute pericarditis
Brain bleed.
Nursing considerations for thrombolytics
Monitor VS, DVT, MI, CVA, bleeding
Take/admin same time each day
Pt. education
Labs: heparin or warfarin
Diet: warfarin (vitK)
Stop smoking
Sensible lifestyle
Hemostatics (aka Antifibrinolytics)
Prevent fibrin from dissolving.
Slows bloodfow
Used to prevent excessive bleeding
IV, PO, topical
Lysteda (tranexamic acid): heavy menses.
Limited use
Floseal, Tisseel, Tachosil
Gel, sponge, when can't cauterize
Dentistry, surgery, military.
Administration of Heparin
Poorly absorbed by GI mucosa because of rapid metabolism by hepatic enzyme, therefore must be given SQ, IV bolus, continuous infusion.
Lab value: aPTT
Do NOT aspirate or massage site of injection.
IM contraindicated d/t bleeding risk.
Antidote: protamine sulfate
Uses for Warfarin
Prevention of MI, DVT, PE in pts undergoing hip or knee surgery or in those with long-term indwelling central venous catheters or prosthetic heart valves. May be given to prevent thromboembolic events in high-risk pts following MI or an a-fib episode.
What is the pregnancy category of Warfarin?
Category X
Drug-Drug interactions with Coumadin
Warfarin's effects are increased with ETOH, NSAIDs, diuretics, antidepressants, steroids, antibiotics, vaccines and vitamins. During warfarin therapy pt should not take any other prescription or OTC drugs unless approved by HCP.
What are s/s of hepatitis and why does the nurse assess for this?
Darkening urine, light/clay colored stools, itchy skin, jaundice or sclera/skin, abd pain (RUQ), in patients with anticoagulant therapy. Drug induced hepatitis is a possible adverse effect of oral anticoagulation therapy.
Antidote for antiplatelet (Plavix) overdose?
Platelet transfusions to prevent hemorrhage.
Sets with similar terms