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robbypowell's version from 2016-10-25 00:14

drugs affecting hemostasis

Question Answer
______ is the classic example of an oral/indirect anticoagulantWarfarin (coumadin)
Warfarin is considered indirect because it acts on the ____ to get its effectLiver → inhib activation of clotting factors (NOT thrombin)
T/F: Warfarin (Coumadin) acts by inhibiting activation of clotting factorsTrue (acts on liver)
T/F: Warfarin (Coumadin) acts by inhibiting activation of thrombinFalse (inhib activation of clotting factors, NOT thrombin)
Clotting factors are activated by ______ carboxylationGamma Carboxylation
T/F: Clotting factors undergo post-translational modificationTrue (gamma carboxylation)
T/F: Clotting factors do not require post-translational modificationFalse (they do, specifically gamma carboxylation)
Gamma carboxylation of clotting factors requires which vitamin and which enzyme to act on that vitamin?Vitamin K (from GIT flora) & Vit K epoxide reductase
Warfarin (Coumadin) blocks what enzyme?Vit K epoxide reductase (necessary for gamma carboxylation of clotting factors)
T/F: Warfarin acts on clotting factors directlyFalse (indirectly) via blocking Vit K epoxide reductase
T/F: Warfarin acts on clotting factors indirectlyTrue (indirectly in liver) via blocking Vit K epoxide reductase (gamma carboxylation of clotting factors)
T/F: Heparin acts on clotting factors directlyTrue (heparin is given via IV, is used for emergency tx and acts on clotting factors directly)
T/F: Heparin acts on clotting factors indirectlyFalse (heparin is given via IV, is used for emergency tx and acts on clotting factors DIRECTLY) ((Warfarin
______ affects hemostasis and is given via IV in emergency situationsHeparin sulfate
______ affects hemostasis and acts directly on clotting factorsHeparin sulfate
______ affects hemostasis and is given orallyWarfarin (Coumadin)
______ affects hemostasis and acts indirectly on clotting factorsWarfarin (coumadin) by acting on Vit K Epoxide Reductase in the Liver (responsible for gamma carboxylation of clotting factors)
______ affects hemostasis by acting on thrombin directly (inhibition)Dabigatran (Pradaxl)
______ (class) such as streptokinase and urokinase are tPA (tissue plasminogen activators) and are given for thrombotic episodesFibrinolytics
Which would you give for a patient with a thrombotic episode... Streptokinase or Epsilonic Aminocaproic acid?Streptokinase (Fibrinolytic) .... (EAA is an antifibrinolytic, and what would fgive for hemophilia patients)
Which would you give for hemophilia patients... Streptokinase or Epsilonic Aminocaproic acid?EAA (anti-fibrinolytic) (give for not enough clotting) ... (streptokinase is a fibrinolytic and would be given for someone with too much clotting)
List the 3 synthetic platelet inhibitorsDipyrimadole (Persantine) (inhibits aggregation), Clopidogrel (Plavix) (ADP receptor antagonist) & Ticlopidine (ADP receptor antagonist)
Of the 3 synthetic platelet inhibitors... 2 act as ADP receptor antagonists... list themClopidogrel (Plavix) & Ticlopidine
Of the 3 synthetic platelet inhibitors... one acts as a platelet aggregation inhibitor... which one?Dipyrimadole (Persantine) (Clopidogrel and Ticlopidine are the other 2... which both act as ADP receptor antagonists)
Antibacterial agents can potentiate Warfarin (coumadin) effects.... why?effect because of dec vit K availability (made by gut flora)
Warfarin (coumadin) has a minimized effect with what 3 drugs classes because of competition of plasma protein binding?NSAIDs, salicylates, anti epileptics (phenytoin is one example)
Which hemostasis affecting drug is a concern with barbiturates b/c they they are microsomal enzyme inducers?Warfarin (coumadin) (liver is site of action)
To get the same effect from Warfarin, while a patient is taking barbiturates, how must the warfarin dosage be altered?Increase (bc it degrades faster)
To get the same effect from Warfarin, while a patient is taking Erythromycin, how must the warfarin dosage be altered?Decrease (warfarin degrades slower, so blood levels higher from same dose)
Which class of drugs interacts with Warfarin by making it less potent (lowering blood concentration)Barbiturates (microsomal enzyme inducers)
Which drug interacts with Warfarin by making it much more potent than it would otherwise be (increasing blood concentration from the same dose)Erythromycin, antibiotic (b/c it is an microsomal enzyme inhibitor)
Synthesis of what clotting factors is affected by Warfarin?2, 7, 9 & 10
Heparin inactivates what clotting factors directly?2, 4, 6, 7, & 8
What is the Reversal agent for Direct Factor 10a inhibitors (Apixaban, Edoxaban, Rivaroxaban((Xarelto)**, fonaparinux (arixtra))Andexanet
What is the reversal agent for Rivaroxaban (Direct Factor 10a Inhibitor)?Andexanet
Andexanet is the reversal agent for what class of drugs?Direct Factor 10a Inhibitors (Apixaban, Edoxaban, Rivaroxaban((Xarelto)**, fonaparinux (arixtra))
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Warfarin (coumadin), Heparin or Platelet Inhibitors (CAN BE MORE THAN ONE RIGHT ANSWER)

Question Answer
Natural (from mast cells)Heparin
released with histamineHeparin (natural from mast cells)
administered parentally
administered orallyWarfarin (coumadin) & Platelet Inhibitors (Dipyrimadole, Clopidogrel, Ticolodipine)
Immediate onset (10-20m)Heparin
Delayed onset (12-24 h)Warfarin (coumadin)
"rapid onset" (1-4 hours)Platelet Inhibitors (Dipyrimadole, Clopidogrel, Ticolodipine)
Principle use: Short term, intensive/controlled anticoagulantHeparin
Principle Use: Long-term, sustained, anticoagulation (via thrombosis prophylaxis)Warfarin (coumadin)
Synthetic drugsWarfarin (coumadin) & Platelet Inhibitors (Dipyrimadole, Clopidogrel, Ticolodipine)
Site of action: Circulating blood (in vivo and in vitro) can be studied in vivo (in the body) or in a test tube (in vitro)Heparin & Platelet Inhibitors (Dipyrimadole, Clopidogrel, Ticolodipine)
Site of action: Liver, (can be studied in vitro only)Warfarin (Coumadin)
Mechanism of action: Activates plasma ANTITHROMBIN III... inc activity of antithrombin by 1000xHeparin
Mechanism of action: Inactivates factors 2a, 4a, 6a, 7a, 8aHeparin (inactivates them directly)
Mechanism of action: Complexes with thrombin & neutralizes thromboplastinHeparin
Mechanism of action: Enhances negative charge on endothelium (repels negatively charged fibrin)Heparin
Mechanism of action: Inhibits hepatic synthesis of factors 2, 7, 9, 10 (all vit K dependent)Warfarin (Coumadin)
Mechanism of action: Inhibits platelet COX and synthesis of TXA2 = failure to aggregatePlatelet Inhibitors
Mechanism of action: Inhibits platelet phosphodiesterase → elevates platelet cAMP = cause failure to aggreatePlatelet Inhibitors
Clinical effect tested with APTT/PTT test (Activated partial thromboplastin time / prothrombin time)Heparin
Clinical effect tested with PTT test aka INR (international normalizing ratio)Warfarin (coumadin)
Clinical effect tested with bleeding timePlatelet Inhibitors
Antidote is Protamine sulfateHeparin
Antidote is Vit K1 or phytonodioneWarfarin
No specific antidotePlatelet Inhibitors
Has a low MW version that can be given subcutanouesly (Lovenox)Heparin
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