Term
what impairs:
clotting factors synthesis
Xa AND IIa
Xa only
IIa only
Va/VIIIa |
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Definition
• Impair Synthesis of Clotting Factors – include Vitamin K antagonists (warfarin)
• Impair Xa and IIa – include UFH, (and LMWH to lesser extent)
• Impair only Xa – includes fondaparinux
• Impair only IIa – includes hirudin, bivalirudin, argatroban
• Impair Va/VIIIa – includes zygris (Protein C concentrate) |
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Term
| • Vitamin K Dependent Factors |
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Definition
| inhibited because they can no longer be activated by carboxylation; include Factors II, VII, IX, X both ex-/intrinsic |
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Term
| warfarin mechanism, administration, metabolism, monitoring |
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Definition
• Epoxide Reductase – warfarin binds this enzyme, used in the recycling of vitamin K
• Administration – only oral anticoagulant, 99% plasma protein bound
• Metabolism – processed by P450 system of liver
• INR – International Normalized Ratio = (Patient PT Time/Normal PT Time)^ISI |
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Term
| caveats of warfarin - hypercoag, delayed effect?, enhanced activity due to, and how to reverse? |
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Definition
• Hypercoagulability – warfarin decreases Protein C levels faster than Factor Xa, thus initial hypercoag
• Delayed Effect – any change in dosing of warfarin has effects which take place only after 2-7 days
• Warfarin Enhancers – many different factors can lead to a stronger warfarin effect:
o Liver disease – P450 system can’t process as fast
o CHF – passive congestion of liver, can’t process warfarin
o Fever/Hyperthyroidism – increased metabolism increased warfarin effect
o Vitamin K deficient – warfarin will really inhibit
• Reversal of Warfarin – can omit doses in mild cases, vitamin K; FFP, PCCs or rFVIIa for serious bleeding w/ elevated INR |
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Term
Heparins: what deactivates only Xa
Xa and weakly deactivates thrombin, and Xa/Thrombin both. |
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Definition
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Term
| which heparin is most likely to cause hep-induced TCP? |
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Definition
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Term
| aPTT is commonly used to monitor UFH and LMWH levels. T/F |
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Definition
| F - LWMH can’t aPTT monitor (only Xa monitoring works) |
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Term
| which drug requires no monitoring due to it's reliable q1d dosing, no TCP risk, and is not affected by other drugs' activity |
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Definition
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Term
Renal clearance is altered in?
dose must be adjusted for renally insufficient patients in? |
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Definition
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Term
| Hirudin, bivalirudin, and argatroban are examples of what class of drugs? |
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Definition
| direct thrombin inhibitors |
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Term
| Hirudin mech, 1/2 life, excretion, monitoring? |
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Definition
has direct inhibition of thrombin through irreversible binding, derived from leeches
o Half-life – has long half-life 4 hours after 1 injection, 18-36 hrs after multiple (hard reversal)
o Excretion – is renally excreted
o Monitoring – must be monitoring using an aPTT test or anti-IIa |
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Term
| bivalirudin mech, 1/2 life, platelets, uses |
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Definition
inhibits both free thrombin and fibrin-bound thrombin
o Mechanism – has specific reversible binding to active site of thrombin
o Half-life – has short half-life 25 minutes, thus can reverse effects easily
o Platelets – does not affect platelet function
o Uses – good choice for patients with heparin-induced TCP; used in interventional cardiology procedures |
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Term
| argatroban mech, metabolism, excretion, no drug-drug interactions, HIT indication? |
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Definition
mimics receptor for thrombin; reversibly inhibits thrombin action; increases all coagulation times
o Metabolism – metabolized by liver; patients with liver disease must be dose-adjusted
o Excretion – by biliary system into feces; can be used in patients w/ renal dysfunction
o No drug-drug interactions – small; also isn’t affected by P450 inhibitors (despite liver met)
o HIT – good choice for patients with heparin-induced TCP |
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Term
| which direct thrombin inhibitor must have adjusted dosing for an alcoholic patient with cirrhosis? |
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Definition
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Term
| which direct thrombin inhibitor must be carefully administered in a px w/ renal insufficiency? |
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Definition
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Term
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Definition
| inhibits GpIIb/IIIa Receptor prevents aggregation (eptifibatide, tirofiban) |
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Term
| drug: inhibits ADP receptor no aggregation or amplification, irreversible, lasts 7-10 days |
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Definition
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Term
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Definition
| irreversibly inhibits COX pathway leading to amplification (sulfinpyrazone, dipyridamole reversible) |
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