Coagulation Drugs Based On Review Flashcards
What happens when Factor X is activated?
Prothrombin is turned into Thrombin
Which pathways does heparin affect?
Intrinsic and common
Which natural inhibitor is heparin most dependent on?
Antithrombin III
Which factors are most affected by heparin
Xa and thrombin
What is the only route of administration for HMW heparin? Why?
IV only. It is a very big molecule (reason its called High molecular weight)
What will happen if you inject HMW heparin IM?
Hematoma
How long does it take for heparin to work?
Immediate
What are the adverse effects of heparin
Hemorrhage
Heparin induced Thrombocytopenia (HIT)
Who should NOT get heparin
During surgery of brain, spinal cord, or eyes=closed spaces. Excess bleeding= major damage
Active bleeds
Hemophilia
Hypersensitive
What are the other two drugs similar to HMW Heparin?
Enoxaprin- low-molecular weight heparin
Fondaparinux- synthetic pentasaccharide
Can enoxaprin and fondaparinux be given Subcutaneously?
Yes thank god
Especially since they are used to replace warfarin in pregnancy- sure would suck to have an IV for your whole pregnancy
What is the reversal agent for Heparin?
Protamine (works right away)
Does protamine work to reverse enoxaprin and Fondaparinux?
Enoxaprin- partially
Fondaparinux- NO effect
What does bivalirudin do?
Direct thrombin inhibitor (alternative to heparin if it caused HIT)
Where does bivalirudin come from?
leeches
Is Argatroban a direct inhibitor of factor Xa like Rivaroxaban, Apixaban, Edoxaban, and Betrixaban?
No. It is a direct inhibitor of thrombin. Tro(m) Ban sound like thrombin idk
Does protamine work for anything other than HMW and LMW heparin
No
What is the MOA of dabigatran (Pradaxa)
It is a direct thrombin inhibitor
Is Pradaxa monitored?
No it has predictable anticoagulant effects
What is the black box warning for Pradaxa
Avoid abrupt discontinuation = big risk of thrombotic events
How do you reverse dabigatran (pradaxa)
Idarucizumab (Praxbind)
What is the MOA for Rivaroxaban, Apixaban, Edoxaban, and Betrixaban?
Direct inhibitors of Xa
What is the route of administration of Rivaroxaban, Apixaban, Edoxaban, and Betrixaban?
ORAL
How do you reverse Rivaroxaban, Apixaban, Edoxaban, and Betrixaban?
Andexxa (Factor Xa decoy)
How do we measure the effects of Rivaroxaban, Apixaban, Edoxaban, and Betrixaban?
You dont. The effect is dose-dependent. (No PT/INR monitoring etc)
What is the MOA of warfarin
Inhibits the reduction of vitamin K and interferes with the synthesis of II, VII, IX, and X (as well as protein C and S)
What factors are effected by warfarin?
II, VII, IX, X****
How long does it take for warfarin to work? Why?
4-5 days.
There will still be factors floating around that were synthesized before you started taking warfarin
How do you need to start warfarin? Why?
Coadministered with Heparin for a few days because it will kill Protein C and S way before the clotting factors, and you will be MORE prone to clots for a few days
Why does warfarin have so many drug interactions?
98% bound to proteins (any change in this status could be dangerous)
CYP450 metabolism
What drugs affect warfarin
Antibiotics (kill the bacteria making your vitamin K)
Estrogen (combined oral contraceptives. Estrogen increases production of clotting factors)
Aspirin
How do you reverse warfarin
Vitamin K (takes time)
Fresh frozen plasma (immediate)
You have a clot. Can you give some heparin, warfarin, pradaxa, etc?
No. They have NO effect on already formed clots.
Need a thrombolytic drug
What is the MOA of Alteplase (tPA) and Tenecteplase?
Convert plasminogen to plasmin
What is another name for Alteplase
Tissue plasminogen activator or t-PA
What are the 3 thrombolytics that are still on the market?
Alteplase (tPA)
Tenecteplase
Urokinase
What makes Tenectaplase special?
It is CLOT SELECTIVE
Higher activity for fibrin-bound plasminogen vs plasma plasminogen
What is the MOA of Urokinase?
Directly activates plasminogen
Is urokinase clot-specific
No
What are the 2 thrombolytics that are off the market
Streptokinase
Anistreplase
You gave your patient some tPA for their DVT and Wooooops now they’re bleeding out. What do you do?
Administer aminocaproic acid or Tranexamic acid
These will inhibit plasminogen activation
Wanna see a list of drugs that are antiPLATELETS not anticoagulants
Aspirin
Clopidigrel
Ticlopidine
Prasugrel
Abciximab
Eptfibatide
Tirofiban
Vorapaxar
How does aspirin prevent platelet aggregation?
Irreversibly inhibits COX enzyme = no thromboxane/prostaglandin synthesis= no platelet aggregation
How does the half life of aspirin compare to the duration of its effects
Effects last much longer than half life. Due to the irreversible inhibition of COX, effects will last the life of the platelet (7-10 days)
How do clopidigrel, ticlopidine, and prasugrel inhibit platelet aggregation?
Irreversibly blocks the ADP receptor
What drug will make clopidigrel not work?
Omeprazole- impairs CYP2C19 and will prevent activation of clopidigrel=clots
Which antiplatelt drugs inhibit the GPIIb/IIIa receptor?
Abciximab
Eptifabatide
Tirofiban
How are Apciximab, Eptifibatide, and Tirofiban administered?
IV only usually during percutaneous coronary intervention procedures (angioplasty, stenting, etc)
What does varapaxar do?
Antagonist of the PAR-1 receptor on platelets (the major thrombin receptor on platelets)= inhibits platelet aggregation
Argatroban and Dabigatran (Pradaxa) are both _______________.
The difference between them is that:
Direct thrombin inhibitors
Argatroban is IV
Dabigatran (Pradaxa) is oral
Which direct factor Xa inhibitors are used the most, and which are used the least
Rivaroxaban and Apixaban: used most (been on market for a long time)
Edoxaban and Betrixaban: used for special cases (non valvular afib or critically ill)
What is plasmin?
It is the active fibrinolytic enzyme
In patients with established heart disease, can aspirin be used as a PRIMARY prevention of cardiovascular events?
No. Used as secondary prevention.
What is the DOC to prevent thrombosis in patients undergoing placement of stents?
Clopidigrel, Ticlopidine, Prasugrel
ADP receptor blockers
What are abciximab, eptifibatide, and tirofiban (the GP IIb/IIIa inhibitors) used for?
They are combined with heparin and given during percutaneous coronary intervention like angioplasty, atherectomy, and stent placement
