Exam 3 Study Qs Anticoagulants Antiplatelets and Fibrinolytics

Question 1

What are the two stages of hemostasis?

Answer 1

Formation of platelet plug, reinforcement of platelet plug with fibrin (coagulation)

Question 2

How does heparin work as an anticoagulant?

Answer 2

Assists antithrombin in inactivating thrombin and factor Xa

Question 3

How does warfarin work as an anticoagulant?

Answer 3

Decreases synthesis of clotting factors dependent on vitamin K

Question 4

How do thrombolytic drugs work?

Answer 4

Promote conversion of plasminogen to plasmin

Question 5

Arterial thrombi cause what kind of injury?

Answer 5

Local injury

Question 6

Venous thrombi cause what type of injury?

Answer 6

Distal injury

Question 7

Name the three categories of drugs for thromboembolic disorders? Where in the vascular system do they work?

Answer 7

Anticoagulants - veins
Antiplatelet agents - arteries
Thrombolytics - veins or arteries

Question 8

What factors does heparin deactivate? What does this prevent?

Answer 8

Assists antithrombin in deactivating thrombin and factor Xa to prevent more venous thrombi.

Question 9

What factor do low molecular weight anticoagulants deactivate?

Answer 9

Factor Xa

Question 10

Which anticoagulant can be given during pregnancy?

Answer 10

Heparin

Question 11

What is the antidote for heparin?

Answer 11

Protamine sulfate

Question 12

Which lab is used to monitor heparin? What is the recommended range?

Answer 12

aPTT. 1.5-2 times the control.

Question 13

What potentially-fatal disorder occurs with heparin?

Answer 13

Heparin induced thrombocytopenia (HIT)

Question 14

List contraindications to heparin

Answer 14

Thrombocytopenia; uncontrollable bleeding; surgery of eye, brain, or spinal cord; lumbar puncture or regional anesthesia.

Question 15

List signs and symptoms indicative of bleeding?

Answer 15

Decreased BP, increased HR, gum bleeding, bruises, petechiae, hematomas, red or black/tarry stools, discolored/cloudy urine, pelvic pain from ovaries, headache or faintness, lumbar pain from adrenal gland

Question 16

Discuss the proper administration of heparin Sub-Q

Answer 16

Lower abdomen, rotate sites; no rubbing; no aspiration; 2” from umbilicus; 25-26 gauges; 1/2 to 5/8 needle; gentle, firm pressure for 1-2 minutes after.

Question 17

List drugs which may increase bleeding with heparin

Answer 17

ASA, antiplatelet drugs, NSAIDS, glucocorticoids

Question 18

What is the antidote for low molecular weight anticoagulants?

Answer 18

Protamine sulfate

Question 19

How does warfarin work?

Answer 19

Interferes with synthesis of Vitamin K-dependent clotting factors

Question 20

Where in the vascular system does warfarin work?

Answer 20

Veins

Question 21

How is warfarin distributed? Can it enter the placenta or breast milk?

Answer 21

Highly-protein bound, crosses placenta and enters breast milk

Question 22

What lab is used to monitor warfarin therapy? What is the suggested range?

Answer 22

PT & INR; INR 2-3 (3-4.5 if mechanical heart valve.

Question 23

Which anticoagulant is Pregnancy Category X?

Answer 23

Warfarin (Coumadin)

Question 24

What is the antidote for warfarin?

Answer 24

Vitamin K (phytonadione), fresh frozen plasma (FFP)

Question 25

List contraindications to warfarin

Answer 25

Active bleeding; severe thrombocytopenia; decreased synthesis of vitamin K (alcoholism, Vitamin K deficiency, liver disease); surgery of eye, brain, & spinal cord; lumbar puncture or regional anesthesia; pregnancy & lactation

Question 26

What would you tell a patient on warfarin who wants to take Tylenol?

Answer 26

Need to monitor INR - 4 325 mg tablets a day for one week can increase risk of elevated INR by 10X (May need to lower warfarin dose)

Question 27

What two drugs increase the synthesis of Vitamin K-dependent clotting factors?

Answer 27

Vitamin K, oral contraceptives

Question 28

What foods are high in vitamin K?

Answer 28

Spinach, kale, lettuce, turnips, greens cabbage, watercress, peas, asparagus, broccoli, oats, whole wheat, green tea, mayonnaise, canola oil, soybean oil.

Question 29

How does dabigatran (Pradaxa) work?

Answer 29

Directly binds thrombin, which prevents fibrin formation and activation of factor VIII.

Question 30

What are the advantages of dabigatran (Pradaxa) over warfarin? Disadvantages?

Answer 30

Less bleeding, faster onset, no blood work, fewer food interactions, fixed dosing, reversal agent Praxibind, GI distress, less experience BID dosing, must give on time.

Question 31

How does rivaroxaban (Xarelto) work?

Answer 31

Directly inhibits factor Xa in clots and serum and inhibits prothrombinase, which prevents fibrin formation. Prevention of stroke and systemic embolization in nonvalvular atrial fibrillation.

Question 32

How does apixaban (Eliquis) work? What is the approved use?

Answer 32

Directly inhibits Factor Xa in clots and serum and inhibits prothrombinase, which prevents fibrin formation. Prevention of stroke and systemic embolization in nonvalvular atrial fibrillation.

Question 33

In what part of the vascular system do antiplatelet agents work?

Answer 33

Arteries

Question 34

List three classes of antiplatelet agents

Answer 34

ASA, P2Y12 ADP receptor antagonists, glycoprotein IIb/IIIa receptor antagonists

Question 35

How does aspirin work? How long are platelets affected? How many days before surgery should aspirin be stopped?

Answer 35

Inhibits COX-1, decreasing platelet aggregation, and inhibits COX-2, decreasing vasoconstriction, 7-10 days.

Question 36

How do ADP receptor antagonists work? How long are platelets affected?

Answer 36

Blocks ADP receptors and prevents platelet aggregation (clopidogrel-Plavix). 7-10 days, take off 5 days prior to surgery.

Question 37

What is a significant adverse blood dyscrasia that may be caused by the ADP receptor antagonist, clopidogrel (Plavix)? What drugs may prevent its action?

Answer 37

Thrombotic thrombocytopenia purpura (TTP). Proton inhibitors may inhibit CYP2C19, which activates clopidogrel (Plavix).

Question 38

How do GP IIb/IIIa receptor antagonists work? Size of effect?

Answer 38

Blocks GP IIb/IIIa receptors & prevents fibrinogen bridges. Large effect, because final step in platelet aggregation.

Question 39

What is the major adverse effect of thrombolytic therapy?

Answer 39

Serious bleeding

Question 40

Which thrombolytic drug is administered as a single IV bolus?

Answer 40

Temectaplase (TKNase)