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87 Cards in this Set
- Front
- Back
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anticoagulant
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a substance that prevents or delays coagulation of the blood
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antifibrinolytic drug
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a drug that prevents the lysis of fibrin and in doing so promotes clot formation
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antiplatelet drug
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a substance that prevents platelet plugs from forming, which can be beneficial in defending the body against heart attacks and strokes
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antithrombin III (AT-III)
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a substance that inactivates three major activating factors of the clotting cascade activated II (thrombin), activated X, and activated IX
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beta-hemolytic streptococci (group A)
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the pyogenic streptococci of group A that cause hemolysis of RBCs in blood agar in the laboratory setting. These organisms cause most of the acute streptococcal infections seen in human beings
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clot
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insoluble solid elements of blood (cells, fibrin threads, etc) that have chemically separated from the liquid (plasma) component of the blood
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coagulation
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the process of blood clotting. more specifically, the sequential process by which the multiple coagulation factors of the blood interact in the coagulation cascade, ultimately forming an insoluble fibrin clot
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coagulation cascade
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the series of steps beginning with the intrinsic or extrinsic pathways ff coagulation and proceeding through the formation of a fibrin clot
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DVT
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the formation of a thrombus in one of the deep veins of the body. the deep veins most commonly affected are the iliac and femoral veins
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embolus
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a blood clot (thrombus) that has been dislodged from the wall of a blood vessel and is traveling throughout the bloodstream. emboli that lodge in critical blood vessels can result in ischemic injury to a vital organ (heart, lung, brain) and result in disability or death.
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fibrin
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a stringy, insoluble protein produced by the action of thrombin on fibrinogen during the clotting process; a major component of blood clots or thrombi
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fibrin-specificity
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property of newer thrombolytic drugs to activate plasminogen to plasmin only in the presence of established clots having fibrin threads versus systemic plasminogen activation throughout the body, which increased bleeding risk. the latter is associated with older thrombolytic drugs known as thrombolytic enzymes
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fibrinogen
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a plasma protein that is converted into fibrin by thrombin in the presence of calcium ions
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fibrinolysis
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the continual process of fibrin decomposition produced by the actions of the enzymatic protein fibrinolysin. it is the normal mechanism for removing small fibrin clots and is stimulated by anoxia, inflammatory reactions and other types of stress.
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fibrinolytic system
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an area of the circulatory system undergoing fibrinolysis
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hemorrheologic drug
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a drug that alters the function of platelets without compromising their blood-clotting properties
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hemostasis
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arrest of bleeding, either by the physiologic properties of vasoconstriction and coagulation or by mechanical, surgical, or pharmacologic means
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hemostatic drug
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a procedure, device, or substance that arrests the flow of blood
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plasmin
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the enzymatic protein that breaks down fibrin into fibrin degradation products; is derived from plasminogen
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plasminogen
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a plasma protein that is converted to plasmin
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pulmonary embolism
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the blockage of a pulmonary artery by foreign matter such as fat, air, tumor, or a thrombus that usually arises from a peripheral vein
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stroke
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occlusion of the blood vessels of the brain by an embolus, thrombus, or cerebrovascular hemorrhage, resulting in ischemia of the brain tissue
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thromboembolic event
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an event in which a blood vessel is blocked by an embolus carried in the bloodstream from the site of its formation. the tissue supplied by an obstructed artery may tingle and become cold, numb, cyanotic, and eventually necrotic (dead)
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thrombolytic drug
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a drug that dissolves thrombi by functioning similarly to tissue plasminogen activator
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thrombus
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technical term for a blood clot; an aggregation of platelets, fibrin, clotting factors, and the cellular elements of the blood that is attached to the interior wall of a vein or artery, sometimes occluding the vessel lumen
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tissue plasminogen activator
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a naturally occurring plasminogen activator secreted by vascular endothelial cells in the walls of blood vessels. thrombolytic drugs are based on this blood component
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Hemostasis is a general term for any process that
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stops bleeding.
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substances that promote coagulation...
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platelets
von Willebrand factor activated clotting factors itssue thromboplastin |
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substances that inhibit coagulation include...
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prostacyclin
antithrombin II proteins C and S |
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once a clot is formed, and fibrin is present,
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the fibrinolytic system is activated
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what is the reversal of the clotting process?
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fibrinolysis
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It is the _____ in the clot that binds to a circulating protein known as _______. this converts _______ to ______. _________ is the enzymatic protein that eventually breaks down the fibrin thrombus into _________
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fibrin
plasminogen plasminogen plasmin plasmin fibrin degradation products |
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What are the drugs that alter platelet functin iwthut preventing them from working
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hemorrheologic drugs
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Which drugs promote blood coagulation?
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antifibrinolytics
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What is a unique difference beween thrombolytic and antithrombotic (anticoagulant) drugs?
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Thrombolytic drugs break down existing thrombi that have already formed.
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What is the main risk of the anticoagulants?
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bleeding
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Heparin works by....
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binding to a substance called antithrombin II, which turns off three main activating factors: activated II (thrombin), X and IV.
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Which of the activating factors is most sensitive to heparin?
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thrombin
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What is the major natural inhibitor of thrombin in the blood?
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AT-III
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What are the major LMWHs?
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enoxaprin (Lovenox)
dalteparin (Fragmin) tinzaparin (Innohep) |
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How do LMWHs differ from unfractionated heparin in action?
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They are more specific for activated factor X (Xa) than for thrombin (II)
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How does warfarin (Coumadin) work?
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It works by inhibiting the synthesis of vitamin K by bacteria in the GI tract. This, in turn, inhibits production of clotting factors II, VII, IX, and X. These four factors are normally synthesized in the liver and are aka vitamin k-dependent clotting factors
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What are the vitamin k dependent clotting factors?
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II, VII, IX, and X (2, 7, 9, and 10)
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What kinds of drug is a glycosaminoglycan? What does it do specifically?
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an anticoagulant. it prevents fibrin formation
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What is the one drug that is a glycosaminoglycan?
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danaparoid
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Danaparoid is similar to what drug?
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lovenox
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What are the 5 antithrombin drugs?
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human antithrombin III (Thrombate)
desirudin (Iprivask lepirudin (Refludan) argatroban (Argatroban) bivilirudin (Angiomax) |
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What are the indications of anticoagulants?
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certain settings in which there is a high likelihood of clot formation:
MI unstable angina a fib indwelling devices conditions in which blood flow may be slowed and blood may pool, such as major orthopedic surgery |
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______ is indicated for prevention of thromboembolic events, while _____ and _____ are indicated for prevention and treatment.
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warfarin;
heparin and LMWH |
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what may be used as a anticoagulant bridge therapy in situations in which a patient must stop warfarin for surgery or other invasive procedures?
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LMWH
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Anticoagulants are contraindicated for.........
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drug allergy
any acute bleeding process thrombocytopenia leukemia or other major blood dyscrasias pregnancy GI obstruction serious inflammation (eg colitis) infection recent surgery |
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What anticoagulant is strongly contraindicated in pregnancy?
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warfarin
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Adverse effects are anticoagulants include......
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systemic or localized bleeding
HITT |
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Risk of adverse effects are increased generally in patients also taking
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high doses of aspirin r other drugs that impair platelet function
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What is HIT?
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an allergic reaction that is mediated by the production of IgG antibodies, the greatest risk of a person with HIT is HITT and subsequent occurrence of thrombosis.
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what is the incidence rate of HIT?
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5-15%
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Drugs that increase the activity of heparin include......
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aspirin
IV ethacrynic acid oral anticoagulants |
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What drugs may partially antagonize the effects of heparin by inducing enzymes that metabolize heparin?
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antihistamines
digitalis tetracyclines |
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What are the symptoms of an overdose of anticagulants?
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hematuria
melena petechiae ecchymoses gum or mucous membrane bleeding |
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What should be done FIRST in the case of a warfarin or heparin OD?
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first, discontinue the drug
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How long does it take to reverse the toxic effects of heparin?
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when DCd, a couple of hours
if protamine sulfate given, 5 minutes |
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What is the antidote of heparin?
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protamine sulfate
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What is the antidote of warfarin?
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vitamin K - phytonadione
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How long does it take to reverse the effects of warfarin OD if the drug is just discontinued and no antidote given?
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36-42 hours
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Why does it take so long to reverse the effects of warfarin?
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Because warfarin functionally inactives the itamin K- dependent clotting factors and because these clotting factors are synthesized in the liver, it may take 36 to 42 hours before the liver can resynthesize enough clotting factors to reverse the warfarin effects.
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How long does it take to reverse the effects of warfarin if vitamin K is given IV?
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about 6 hours
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If a large dose of vitamin K is given for warfarin OD, what might happen?
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Warfarin resistance is likely to occur, because a large dose of vitamin K will maintain its warfarin reversal effects for up to 1 week.
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T or F: the other drugs lack highly specific antidotes, but danaparoid also responds partially to protamine
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T
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What else may be done for antithrombin OD?
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transfusion and hemodialysis
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of the anticoagulants, which are available for oral use?
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warfarin only
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most of the anticoagulants are administered ____________ and ______, but never __________.
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IV and SC, but never IM
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Why are the anticoagulants never administered ______?
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because of their propensity to cause anticoagulation with large ecchymoses at the site of injection
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What lab MUST be monitored with heparin therapy?
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aPTT
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What lab study must be monitored with warfarin?
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PT/INR
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What is PT/INR tell us?
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It is a standardized measure of the degree to which a patient's blood coagulability has been reduced by the drug
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What is a normal INR without warfarin?
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1.0
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What is a therapeutic INR with warfarin?
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2 to 3.5
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Why is laboratory monitoring not that necessary with the LMWHs like lovenox
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Because of it high bioavailability and greater affinity for factor Xa
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What drugs have similar pharmacology to enoxaparin?
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danaparoid and fondaparinux
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What is used specifically for HIT? how is it monitored?
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lepirudin (Refludan) and argatroban; using the aPTT
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What anticoagulant is used for hereditary deficiency?
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human antithrombin III
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What anticoagulant is used for DVT prophylaxis?
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desirudin
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What anticoagulant is used for unstable angina?
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bivalirudin
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What is argatroban used for?
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HIT and for PCI percutaneous coronary intervention procedures in patients at risk for HIT
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What is better for monitoring the effectiveness of warfarin, PT or aPTT?
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PT
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What is better for monitoring the effectiveness of heparin, PT of aPTT
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aPTT
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Anticoagulant drugs work in the clotting cascade, while antiplatelet drugs work to ......
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prevent the platelet adhesion to the site of blood vessel injury, which actually occurs before the clotting cascade.
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