Anticoagulants

Question 1

ASA

Answer 1

Antiplatelet drug (cyclooxygenase
inhibitor)
Works through inhibition of platelet
aggregation
Is useful primarily in prevention of
thrombosis of arteries
Cardiac, thrombotic stroke

Question 2

warfarin

Answer 2

Vitamin K antagonist
Works through inhibition of the
enzyme needed to activate vitamin k
Is useful primarily in prevention of
thrombus in veins and atria of the
heart (A fib)
Requires INR monitoring

Question 3

Heparine

Answer 3

Can be given IV or sub q
* Cannot be given oral as it can not be
absorbed through the gut

Question 4

LMW Heparin

Answer 4

Always given sub q
* Dalteparin
* Enoxaparin
* Fondaparinux

Question 5

HEPARIN (UNFRACTIONATED)

Answer 5

• Consists of long polysaccharide chains
• Does not readily cross membranes because of structure
• Therefore, can be used for pregnant and breastfeeding
  women
• Helps antithrombin inactivate clotting factors
  (thrombin and Xa)
• Prevents formation of fibrin
• Requires frequent PTT monitoring
• Effect is rapid onset (minutes after administration and
  therefore works well in urgent situations)

Question 6

Dabigitran (advantage)

Answer 6

Oral anticoagulant with several advantages over warfarin
* Rapid onset
* No need for monitoring of anticoagulation
* Few drug food interactions
* Lower risk of major bleed
* Same dose used for all patients

Question 7

Dabigitran (Indication, MOA, AE, DI)

Answer 7

Thrombin inhibitor
* Inhibits free thrombin and thrombin bound to clots
* Used for stroke prevention and in those with Afib
* Dose for stroke prevention is 150mg BID
* Excretion is primarily renal
* Should be stopped prior to surgery
* Side effects include dyspepsia and gastritis
* Should not be given with P-glycoprotein inhibitors such as
ketoconozole, quinidine (could cause bleeding)

Question 8

antidote for Dabigitran

Answer 8

Idarucizumab, which is given as an intravenous bolus at a dose of 5
grams, rapidly reverses the anticoagulant effect of dabigatran.

Question 9

DIRECT FACTOR XA INHIBITORS

Answer 9

Riviroxaban, Apixaban, Edoxaban
* Are all oral
* Advantages over heparin and warfarin include fixed dosing
and no need for INR monitoring
* Also rapid onset, lower bleeding risk, few drug interactions,
* Disadvantage is - unsafe in pregnancy
* Can accumulate in people taking P-glycoprotein inhibitors
(ketaconozole) and CYP3A4 inducers and induce bleeding
* Effectiveness of Apixaban is decreased in those taking St Johns Wort, phenytoin, carbamazepine, rifampin)

Question 10

antidote for DIRECT FACTOR XA INHIBITORS

Answer 10

Andexxa

Question 11

Clopidogrel (Plavix)

Answer 11

Suppresses platelet aggregation by blocking P2Y12ADP receptors on
the platelet surface, preventing aggregation
* Clopidogrel causes irreversible receptor blockade

Question 12

Ticagrelor

Answer 12

Causes reversible receptor blockade
* Used for secondary prevention of atherothrombotic events in ACS
* Taken orally
* Can cause serious bleeding

Question 13

Plavix indication

Answer 13

Taken to prevent stenosis of coronary stents and secondary
prevention of MI and stroke
* In those with ACS it is combined with ASA
* Most common AE is dyspepsia, diarrhea and rash
* Increased bleeding risk therefore should be d/c before surgery (5
days prior)

Question 14

P2Y12 ADENOSINE DIPHOSPHATE RECEPTOR ANTAGONIST
ANTIPLATELET DRUGS

Answer 14

Clopidogrel and Ticagrelor