Anticoagulants Flashcards
What are the three pro-coagulants used in primary hemostasis?
vWF, clotting factor VIII, ADP
When platelet aggregation begins, what two things are used as a connecting agent?
vWF and fibrinogen
What does thromboxane do?
causes vasoconstriction and degranulation of adjacent platelets
What things cause vasoconstriction?
serotonin, histamine, and thromboxane
What does ADP do?
promotes adhereance and degranulation
What agents are released in degranulation?
serotonin, histamine, thromboxane, AD), clotting factors, and platelet factor 4
What Xa do?
Xa makes prothrombin turn to thrombin, and thrombin makes fibrinogen to fibrin
Lysis is mediated by?
plasmin, plasmin splits fibrin and fibrinogen to FDPs
What are the oral anti platelet agents?
Aspirin, Ticlopidine, Clopidogrel, Prasurgrel, and Ticagrelor
What are the IV anti platelet agents?
Abciximab, Eptifibatide, and Tirofiban
What is the only anti platelet aggregation agent used proactively?
Aspirin
COX inhibitos (ASA) prevents the production of what?
Thromboxane A2 (Prevents the stickiness)
What is Ticlid
An older drug used for PVD that causes neurtropenia, TTP, GI upset and teratogenesis
DO Aspirin and Plavix deactivate or destroy platelets and is the platelet count normal?
Deactivate, and plt count is normal
What class is Plavix?
Thienopyridine, irreversibly blocks ADP receptor on platelet and inhibits fibrinogen binding
Plavix is metabolized by what? and do you need to alter dosing in renal or hepatic failure?
CYP, and yes renal or hepatic dosing required
What is Prasugrel (Effient) used for?
For ppl genetically immune to plavix. but has a greater risk of bleeding but more effective at plt aggregation reduction. , greater risk of hemorrhagic events
How does Ticagrelor (Brilinta) work?
blocks ADP receptors from ALLOSTERIC (different) binding sites. higher rate of intracranial and non procedure related bleeding. prevents recurrent ishcemic events after MI. stroke, ACS. ALWAYS combine with ASA unless contraindicated.
What are the GPIIb/IIIa inhibitors and how do they work?
Aciximab (reopro)
Eptifibatide (integrilin)
Tirofiban (Agrastat)
Blocks the GPIIb/IIIa receptor preventing fibrinogen binding.
Abciximab is used for?
ACS with planned PCI. RENALY DOSE:
creat <2 give 2mcg/kg/min up to 72 hours
creat 2-4 give 1 mcg/kg/min up to 72 hours
What do you reverse Abciximab and Eptifibatide & Tirofiban with?
Abciximab- plts
Eptifibatide and Tirofiban discontinue.
Antiplatelet therapy should cease how many days before surgery?
7-10 days; and resume 24 hrs post op as long as hemostasis achieved.
Heparin is what type of agent?
Antithrombotic; it activates Antithrombin III, increases inhibition of thrombin and factor Xa by 1000 fold.
HIT- what is type I and Type II
Type I- non immune begins 4 days after start, NOT progressive or associated with thrombosis
Type II is immune mediated and follows 5-14 days after exposure.
Reduction in pot count <15,000 or drop 50% from baseline
What is HITT?
thrombocytopenia with thromboembolism (10-25% of cases)
Venous>arterial
What are the test for HIT?
ELISA and SRA.
How does Enoxaparin (Lovenox) work?
LMWH. binds with antithrombin III and inhibits Factor Xa. Used for ACS and DVT prophylaxis
Pros of Lovenox?
dont routinely monitor, but can check anti-Xa levels. Preggo women, really monitor these levels. not for use with spine surgery or patents with epidural catheters. Protamine has a 60% reversal.
What does Fondaparainux (Arixtra) do and what are its pros and cons?
Does NOT work on thrombin like heparin!
Synthetic factor Xa inhibitor- binds with antithrombin III to potentiate Xa inhibition (by 300) times. no direct effect on II a (thrombin). Cons: no reveal agent. FFP INEFFECTIVE IN REVERSAL. give supportive care. Contraindicated in CrCl <30ml/in and spinal or lumbar puncture.
What are IV Direct Thrombin (IIa) inhibitors?
Do not require Antithrombin III, include Hirudin, Lepirudin, Desirudin, Hirulog, Argatroban, Bivalirudin, used for hIT or PCI
What IV Direct Thrombin (IIa) inhibitors can only be used once due to anaphylaxis?
Lepirudin and Desirudin
What do IV Direct Thrombin (IIa) inhibitors require for overdose/bleeding?
combo of Factor VII, FFP, and cyro (kitchen sink)
What does Wafarin do?
Interferes with production of Vitamin K dependent clotting factors (II, VII, IX, X)
Interferes with the carboxylation of natural anticoagulants Protein C and Protein S
What increases the effects of Warfarin?
Amiodarone, Cimetidine, Acetaminophen, Phenylbutazone
What decreases the effects of Warfarin?
Carafate, Cholestyramine, Spironolactone, Barbituates, Vitamin K containing foods
Reversal for Warfarin
FFP and Vitamin K
What are the New Oral Anticoagulants?
Dabigatran (Pradaxa); Rivaroxaban (Xaralto); Apixaban (Eliquis)
Dabigatran- no monitoring, less diet interactions, high cost, BID dosing, and no antidote
Rivaroxaban, no monitoring, less diet interactions, 1x/day dosing, no antidote tho
Apixaban, BID dosing, sort of reversal, no routine monitoring, and less diet and drug interactions.
What are Fibrinolytic agents?
Clot busters (not heparin)
What are Streptokinase and Urokinase used for?
Streptokinase- anaphylaxis associated with this
Urokinase- unclot a line
What are TPA and TNKase?
Fibrinolytics; TPA: Alteplase and Reteplase are the most common agents. TNKase is popular for restoration of flow after a STEMI, one time dosing makes it popular. use within 6 hours.
Absolute contraindications with Fibrinolytics?
Previous hemorrhagic stroke Ischemic stroke within 3 months Known intracranial neoplasm Active internal bleeding suspected aortic dissection closed head trauma within 3 months
What are relative contraindications with fibrinolytics
Severe uncontrolled HT (BP >180/110)
History of severe chronic HTN
current use of anticoagulants or hemophilia
non compressible vascular puncture (subclavian)
Recent tram within 2-4 weeks including CPR
Major surgery within 3 weeks
recent (2-4 wks) internal bleeding or active PUD
pregnancy
for streptokinase- allergy or prior exposure (5 days to 2 years)
