BL- Antithrombotic drugs Flashcards Preview

BL/DD USMLE and Basics > BL- Antithrombotic drugs > Flashcards

Flashcards in BL- Antithrombotic drugs Deck (46)
Loading flashcards...
1
Q

interfere with the coagulation cascade and prevent thrombin formation.

A

Heparin and oral anticoagula

fibrinolytin–> thrombin–> fibrin

2
Q

They lyse clots by increasing formation of plasmin

A

Fibrinolytic agents

fibrin–> plasmin–>degrade product

3
Q

inhibit formation of platelet products or

block platelet adhesion preventing platelet aggregation and clot formation

A

. Anti-platelet agents.

4
Q

Proteoglycan with sulfated polysaccharides of varying lengths (~12,000 daltons). Made from pig intestine.

A

Unfractionated Heparin

5
Q

Depolymerized heparin- (~4500 daltons).

Better pharmkintetics

A

Low Molecular Weight Heparin (LMWH).

6
Q

Synthetic pentasaccharide (5) corresponding to the minimal sequence in heparin for binding anti-thrombin.

A

Fondaparinux. (type of heprin)

binds antithromin 3

7
Q

Examples of pathologic thrombi formation

A

Formation of thrombus in atrial fibrillation

Formation of deep vein thrombus (DVT)

Formation of thrombus on atherosclerotic plaque

8
Q

Fibrin

A

required for a stable clot

9
Q

Three types of heprin

A

Unfractionated Heparin
Low Molecular Weight Heparin (LMWH)
Fondaparinux

10
Q

Current Heprin Concerns

A

shortage- sourced by China

contamintaion- chondroitin sulfate

11
Q

What does Heprin bind?

A

Antithrombin 3

12
Q

How does heprin work

A

helps antithromin 3 inactivate coag factors

13
Q

______dependent differences in action of heparins

A

Size

14
Q

Unfractionted heprin binds

A

AT-3
2a
10a

15
Q

Low molecular weight heprin (LMWH ) binds

A

AT-3

10a

16
Q

Unfractionted heprin route/pharmkinetics

A

IV or Sub-Q
Does not cross placenta
Unpredictable dose response
Requires hospital admission and monitoring.

17
Q

LMWH and fondaparinux route/pharmkinetics

A

Administered sub-cutaneously

Better bioavailability, more predictable dose response, longer half-life

Less monitoring (outpatient)

18
Q

Uses of Heparins

A

Coronary angioplasty
stent placement
Surgery requiring cardiopulmonary bypass
Kidney dialysis

19
Q

Uses of Heparins

*Used with warfarin

A

Venous thrombosis, pulmonary embolism (heparins act rapidly)
(Abdominal surgery, hip and knee replacement)

20
Q

Uses of Heparins

✪Used with fibrinolytics

A

myocardial infarction✪

21
Q

Toxicity of Heparins

A
  1. Bleeding
  2. Heparin-induced thrombocytopenia
  3. Allergic Reaction
22
Q

a. Discontinue drug

b. Effects are reversed with protamine sulfate.

A

Toxicity of Heparins

Bleeding

23
Q

Oral Anticoagulants

A

Warfarin

24
Q

Pharmacokinetics of Warfarin

A

Rapidly absorbed
Good bioavailability
Long half-life
Slow onset of action

25
Q

Warfarin Used to prevent

A

Venous thromboembolism (used with heparin)

Embolism in patients with prosthetic valves or atrial fibrillation

Stroke, recurrent infarctions

26
Q

a. Low platelet count due to production of AB to plt factor 4/heparin complexes. ABs bind to plts and induce a pro-thrombotic state.
b. Less common with LMWH and fondaparinux
c. Direct thrombin inhibitors used as anti-coagulants Argatroban, Lepirudin

A

Heparin-induced thrombocytopenia

27
Q

Warfarin: Adverse effects and problems

A

Hemorrhage- administer vit. K/plasma

Crosses placenta - teratogenic

Drug interactions/food

Delayed onset of action

Requires monitoring

28
Q

Dicumarol

A

precursor of warfrin

29
Q

Warfrin is a _____ antagonist

A

Vit.K

30
Q

a. Due to the contaminant oversulfated chondroitin sulfate

b. Activation of the contact system (bradykinin, complement)

A

Allergic Reaction to heprin

31
Q

New oral anticoagulants

A

Direct thrombin or Factor Xa inhibitors

32
Q

Direct thrombin or Factor Xa inhibitors Advantages

A

Rapid onset of action
Absence of food interactions
Do not require monitoring

33
Q

Direct thrombin or Factor Xa inhibitors

Disadvantages

A
*Contraindicated with kidney disease
Greater GI bleeding than with warfarin
Short half-life
Cost (20X> warfarin)
**No antidote to reverse effects
34
Q

Oral prodrug, a potent direct thrombin inhibitor

Lower rates of stroke and systemic embolism than with warfarin

Less intracranial hemorrhage (but increase in MI)

No antidote available to reverse its effects

A

Dabigatran etexilate (Pradaxa) for afib/VTE

35
Q

Direct inhibitors of Factor Xa

Superior to warfarin in preventing strokes and emboli for treatment of atrial fibrillation

A

Apixaban (Eliquis), FDA approved for afib

Rivaroxaban (Xarelto), FDA approved in 2011 for afib/VTE

36
Q

Dabigatran etexilate (Pradaxa) for afib/VTE

A

Oral prodrug, a potent direct thrombin inhibitor

Lower rates of stroke and systemic embolism than with warfarin

Less intracranial hemorrhage
INC in MI

No antidote available to reverse its effects

37
Q

Apixaban (Eliquis), FDA approved for afib

Rivaroxaban (Xarelto), FDA approved in 2011 for afib/VTE

A

Direct inhibitors of Factor Xa

Superior to warfarin in preventing strokes and emboli for treatment of atrial fibrillation

38
Q

Tissue plasminogen activator

A

Serine protease
convert plasminogn to plasmin
plasmin degrades fibrin
(desolves clot)

39
Q

Uses of Fibrinolytic drugs

A

ER rx for:

acute myocardial infarction

Ischemic stroke

Deep vein thrombosis and pulmonary embolism

40
Q

Adverse effects of Fibrinolytic drugs

A

Hemorrhage from lysis of “physiological clots”

Induce a systemic lytic state due t increased plasmin formation

41
Q

Inhibits thromboxane A2 production by irreversibly inactivating cyclooxygenase 1.
Anti-platelet Drugs

A

Aspirin

42
Q

Aspirin uses

A

after AMI and thrombotic stroke (with thrombolytics) to prevent AMI and stroke in high-risk patients

Anti-platelet Drugs

43
Q

ADP receptor blockers

A

Clopidogrel (PLAVIX)

Ticagrelor

44
Q

Bind IRREVERSIBLY to ADP receptor.

Block alpha granule secretion and expression of adhesion proteins, GPIIb/IIIa

Slow onset of action

Used to prevent AMI and thrombotic stroke (with aspirin)

A

Clopidogrel- PLAVIX

45
Q

Binds REVERSIBLY to ADP receptor

Acts more rapidly

A

Ticagrelor

46
Q

block binding of fibrinogen to
the adhesion protein GPIIb/IIIa.
Anti-platelet Drugs

A

Glycoprotein IIb/IIIa inhibitors