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Pharmacology Unit 2 > Thrombosis > Flashcards

Flashcards in Thrombosis Deck (24)
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1
Q

What is the indication of use of an anticoagulant, and what are the general classes?

A
  • use for VENOUS thromboembolism (prophylaxis or treatment - clot preventer)
  • indirect thrombin inhibitors (heparins), vitamin K antagonists, direct thrombin inhibitors, and direct Xa inhibitors
2
Q

What is the indication of use of a fibrinolytic drug?

A
  • ACUTE arterial and venous thrombosis (lysing already formed clots - clot buster)
3
Q

What is the indication of use of a antiplatelet drug?

A
  • ARTERIAL thrombosis
4
Q

What is the mechanism of action of heparins?

A
  • bind to antithrombin and potentiate formation of anti-thrombin coagulation factor complex (IIa, Xa, IXa, XIa, XIIa)
5
Q

What does standard unfractionated heparin inhibit?

A
  • Factor Xa and thrombin
6
Q

On your surgery rotation, an elderly patient is put on prophylactic heparin pre-op. The surgery goes well but the patient wakes up confused and falls out of bed, hard. What do you administer to counteract the action of heparin?

A

protamine sulfate (highly basic peptide that binds heparin)

7
Q

How do you monitor effectiveness of heparin, and what are two major side effects to watch out for?

A
  • monitored with PTT

- heparin induced thrombocytopenia and thrombosis

8
Q

What does low molecular weight heparin inhibit? What are the names of the three LMWHs?

A
  • Factor Xa (inhibits thrombin less effectively due to smaller size and lack of binding)
  • dalteparin, enoxaparin, tinzaparin
9
Q

What does fondaparinux inhibit and what special condition can it be administered in?

A
  • activates anti-thrombin to inhibit Xa

- can be given in HIT, but cannot be reversed if serious bleeding occurs

10
Q

What factors do Vitamin K antagonists affect?

A

Factors II, VII, IX, X, protein C, protein S

11
Q

Alternative compounds (i.e. other drugs) binding to what protein displaces warfarin and can increase endogenous activity?

A

albumin

12
Q

How do you monitor warfarin effectiveness and how is that value expressed clinically?

A

monitor PT, which is expressed as INR

INR = [PT patient/PT control] x international sensitivity index

13
Q

You start a patient on warfarin and two days later, she ends up in the ER with a pulmonary embolism. What did you forget about warfarin?

A

Warfarin inhibits carboxylation of protein S and C, which temporarily shifts the balance toward coagulation at the onset of therapy

14
Q

How are direct thrombin inhibitors’ effectiveness monitored and how are they reversed?

A

monitored by PTT and cannot be reversed

15
Q

What procedure are lepirudin and bivalirudin approved for?

A

Percutaneous cardiac interventions

  • directly inhibits thrombin
16
Q

What condition is argatroban used for?

A

HIT

  • inhibits the catalytic site of thrombin
17
Q

How is dabigatran administered and how does it work?

A

orally, works as competitive inhibitor of thrombin but there is still no reversibility or antidote

18
Q

What two drugs are direct Xa inhibitors, and what are some drawbacks to use?

A
  • Rivaroxaban and apixaban

- no specific antidotes and no method to assess levels in serum

19
Q

How do fibrinolytics (such as tPA, streptokinase, or urokinase) work?

A

induce activation of plasminogen which converts to plasmin and degrades fibrinogen, coagulation factors, and plasminogen

20
Q

How does aspirin’s antiplatelet action work?

A
  • irreversibly inhibits COX in platelets, which prevents TXA2 formation and prevents platelet aggregation
21
Q

Which antiplatelet drug works by causing an increase in platelet cAMP, which decreases platelet aggregation?

A

dipyridamole (a phosphodiesterase inhibitor)

22
Q

Which antiplatelet drug works by inhibiting platelet ADP receptors?

A

clopidogrel

23
Q

What drug antagonizes GPIIb-IIIa? What is the effect of this drug that limits its use?

A

Abciximab, a monoclonal antibody

  • elicits an immune response, so this drug is once in a lifetime
24
Q

What drugs compete with fibrinogen and vWF binding to GPIIb-IIIa?

A

eptifibatide and tirofiban (fibrinogen analogs)