6Nov Anticoagulant Flashcards | Quizlet Posted by: admin Categories: Pulmonary Embolism Comments Off on Anticoagulant Flashcards | Quizlet Anticoagulant Flashcards | Quizlet General information about heparin heterogeneous mixture of polysaccharide chains derived from cows/pigsanticoagulant used when rapid anticoagulant effect is required Heparin pentasaccharide need what groups for binding? What are the indications for heparin clot prevention, ACS (acute MI, post MI and unstable angina), DVT, clear IV lines dialysis Explain the 5 steps in the pharmacology of heparin 1. heparin binds to antithrombin III (AT III Thrombate) and produces conformational change that increases AT III binding to thrombin (IIa) and Stuart factor (Xa)2. AT-III inhibits serene proteases on specific activated clotting factors (AT III activity slow and gradual by itself)3. main clotting factors inhibited IIa, Xa (1:1 activity)4. after AT-III binds to the clotting factors, heparin dissociates and binds to different AT-IIIs over and over5. heparin inhibits IIa and Xa, has no fibrinolytic activity What is a major ADR of heparin transient thrombocytopenia for heparin induced thrombocytopenia: induces antibodies which destroy platelets, also attack the lining of blood vessels which can trigger the coagulation cascade What is used to monitor heparins action aPTT (activated partial thromboplastin time)normal baseline 20-30 sectherapeutic range: 1.5-2.5 x baseline What is the antidote to heparin what are the advantages to using LMWH over regular heparin decreases non-specific binding to plasma ptns less binding to platelets (decreases HIT)more predictable response and decreased need to monitorlonger T1/2 than heparin so less frequent dosing What is the range of # of saccharide lengths for LMWH and UH? What are the indications of LMWH IV, SC agents used for DVT, PE, unstable angina/AMI activate AT-III which bind Xa and to a lesser extent bind IIa causing inactivation What drug is an indirect Xa inhibitor and what is special about it? fondaparinux-arixtrait is a synthetic pentasaccharide and the need for monitoring with it is low What is the pharmacology of fondaparinux? inhibits Xa indirectly, only activating AT-III What is a contraindication of fondaparinux? What are the advantages of direct Xa (stuart-factor) inhibitors? A disadvantage? advantages:routine coagulation monitoring not requiredoral agents quicker onset as pt transitions from hosp to outpt these agents are better than warfarin at establishing therapeutic blood levels quicker following procedures disadvantage: no reversal agent yet What are the indications of apixaban and rivaroxaban venous thromboembolism prophylaxis following knee or hip surgery/ prevent pulmonary embolismPrevention of stroke in pts with a fib (PSAF) What are some cautions regarding the stopping of rivaroxaban and apixaban discontinuing abruptly w/o initiating some other anticoagulation increases risk of stroke caution/avoid with strong dual inhibitors of CYP3A4 and P-gp. decrease dose or avoid with ketoconazole, itraconazole, ritonavir, and clarithromycincaution/avoid with strong inducers of CYP3A4: rifampin, carbamazepine, phenytoin, st johns wort general information about andexanet recombinant modified human factor xa decoy ptnindicated in pts treated with Xa inhibitors modified recombinant derivative of factor Xa which acts as a decoy receptorhigher affinity to Xa inhibitor than natural XaXa inhibitor binds to andexanet rather than to endogenous Xa general information on direct 2a inhibitors routine coagulation monitoring unnecessary predictable pharmacokinetics, faster onsetless potential for drug-drug interactionscapsules expire 120 days after bottle is openedkeep caps in original storage bottle, only remove 1 cap at a time indications for dabigatran etexilate decreases stroke and systemic embolism in pts with a fib what are the pharmacokinetics and pharmacology of dabigatran etexilate pharmkineticsprodrug converted to active dabigatran by serum esterases pharmacologybinds directly to activated thrombinbound to fibrin in clot and circulating in blood you should use caution with dabigatran in people with a crcrl of 15-30 ml/min (has potential for severe bleeding in pt with decreased renal function) important info on idarucizumab reversal agent indicated in pts treated with dabigatran with uncontrolled bleedingbinds 350x higher affinity for dabigatran than thrombin vitamin k antagonist, oral anticoagulant. requires strict compliance from pt What are the indications for warfarin post MI and venous thrombosis (prophylaxis and treatment)prophylaxis of embolism in pts with a fib inhibits vitamin k epoxide reductase complex 1: VKORC1induces a state of vit k deficiency in the liverdecreases vit k available as a cofactor for activation of vit k dependent clotting factorsdecreases production of vit k dependent clotting factors (prothrombin and factors 7,9/10) by synthesizing biologically inactive clotting factorspcol effect delayed due to clotting factor T1/2does not dissolve pre-existing thrombus yet does prevent further thrombi formation Which isomer of warfarin is more potent What are drug interactions with warfarin drugs that also cause bleeding (high dose ASA and NSAIDs) food interactions with warfarin foods rich in vit k and alcohol Source link Tags: surgery
