Anticoagulation

Question 1

3 classes of anti-thrombotic medication

Answer 1

primary hemostasis - platelet adhesion, activation, aggregation - antiplatelet

secondary hemostasis - coagulation cascase - anticoagulants

thrombolytic medication

Question 2

Anti-platelet medications

Answer 2

COX inhibitors
phophodiasterase inhibitors
ADP receptor antagonists
GP IIB/IIIA receptor antagonists

Question 3

COX inhibitors non-selective

Answer 3

ASA - irreversible

NSAIDs - reversible

Question 4

Selective COX 2 inhibitors

Answer 4

Celebrex 30:1

Vioxx 300:1 - increased MI, withdrawn from market

Question 5

Phosphodiasterase Inhibitors

Answer 5

Dipyriamole - inhibits phosphodiasterare which increases cAMP, decreased response to ADP = no aggregation

Question 6

ADP receptor antagonists

Answer 6

Indirect: ticlopidine, clopidogrel, and prasugrel: inactive require activation in liver by CYP450, irreversible inhibition of ADP

direct: Cangrelor and Ticagrelor: reversible

Question 7

GP IIb/IIIa antagonists

Answer 7

abciximab, eptifibatide, tirofiban

contraindicated with history of surgery in past 4-6 weeks

Question 8

Anti-coagulants

Answer 8

Vitamin K antagonist
glycosaminoglycans
pentasaccharides
direct thrombin inhibitors
activated protein C

Question 9

Vitamin K Antagonist

Answer 9

Warfarin

vitamin K dependent factors 1, 7, 9, 10

Question 10

Glycosaminioglycans

Answer 10

inhibits 2a, 9a, 10a, 11a, 12a by accelerating the inactivation by antithrombin by 1000 times

LMWH: inhibits 2, 10 at a 1:4 ratio with less protein binding making more consistent administration

Question 11

Pentasaccharides

Answer 11

Fondaparinux: inactivates factor X via antithrombin

Question 12

Direct Thrombin Inhibitors

Answer 12

1. uni-valent: argatroban - bind to site on thrombin
2. bi-valent: lepirudin and bivalirudin - bind to two sites on thrombin

inhibit both circulating and fibrin bound thrombin

Question 13

Activated Protein C

Answer 13

inactivates factor 5 and 13

Xigris

Question 14

Direct Factor Xa Inhibitor - new

Answer 14

rivaroxaban
apixaban

no monitoring, no antidote

Question 15

Direct Thrombin Inhibitor - new

Answer 15

dabigatran

no monitoring, no antidote

Question 16

Thrombolytic Medications

Answer 16

t-PA: alteplase, reteplase, tenecteplase
UPA: urokinase

*more capable of dissolving new clots versus older clots

Question 17

Protamine

Answer 17

heparin reversal, partial reversal of LMWH

1 mg to 100 units of heparin - administer over 5-10 minutes

side effects; histamine release promotes peripheral dilation, serotonin and thromboxane release promotes pulmonary vasoconstriction and R sided HF, and hypotension antibody mediated reaction

Question 18

Vitamin K

Answer 18

1-1.5 mg IV or 2.5 mg PO takes 24-48 hours

anaphylaxis, dyspnea, chest tightness

Question 19

Blood Product Reversal of Warfarin

Answer 19

recombinant factor 7 - 10-90 mcg/kg

prothrombin complex concentrate 25-50 IU/kg

FFP 10-15 ml/kg

Question 20

Anti-fibrinolytics

Answer 20

Amicar and TXA

bind to plasminogen

Question 21

Cardiac Stents

Answer 21

bare metal 4-6 week

DES 1 year

Question 22

Neuraxial Anesthesia - thrombolytics

Answer 22

contraindicated

Question 23

Neuraxial Anesthesia - warfarin

Answer 23

normal INR, remove <1.5

Question 24

Neuraxial Anesthesia - LMWH

Answer 24

twice daily dosing 24 hours after surgery

remove catheter 2 hours before first dose

Question 25

Neuraxial Anesthesia - heparin

Answer 25

twice daily dosing <10,000 U

IV 1 hour after insertion

remove 2-4 hours after last dose

Question 26

Neuraxial Anesthesia - antiplatelet

Answer 26

NSAIDs okay

discontinue others days prior