Phamacology

Question 1

Warfarin (Coumadin) MOA

Answer 1

Inhibition of vitamin K dependent coagulation factors II, VII, IX, X
Also inhibits Protein C and S

Question 2

Warfarin Indications for use

Answer 2

Venous and arterial thromboembolism
Pulmonary embolus
Stroke prevention in atrial fibrillation
Thrombus prevention in cardiac valve replacement
Stroke
Transient ischemic attacks
Prevention of clots

Question 3

Therapeutic INR

Answer 3

For most indications the INR range is 2.0-3.0
Normal INR is 1.0
Not therapeutic until INR is 2.0

Question 4

Warfarin Dosing

Answer 4

A safe place to start is with 5 mg nightly

Adjust dose as needed to achieve desired INR

Question 5

interactions that are likely to decrease the INR

Answer 5

Vitamin K containing foods (dark leafy greens, green tea)

Smoking/tobacco decreases INR

Alcohol increases the INR

Question 6

Adverse events with Warfarin

Answer 6

Bleeding, bleeding, bleeding

Skin/tissue necrosis leading to gangrene
Usually occurs 3-8 days after starting
Purple toe syndrome (3-8 weeks after starting)

Question 7

How often should the INR be checked after each dose change?

Answer 7

2-3 days

Question 8

How long should warfarin be held when anticipating a surgical/invasive procedure?

Answer 8

3-5 days

Question 9

Heparin mechanism of action

Answer 9

Potentiation of the action of antithrombin III and inactivating thrombin, IX, X, XI, XII, and plasmin

Prevents the conversion of fibrinogen to fibrin

Question 10

Heparin Monitoring

Answer 10

Frequent monitoring of PTT is needed for a narrow therapeutic window.

Question 11

Heparin CI and Adverse Effects

Answer 11

Contraindications: anaphylaxis and recent major surgery

Adverse effects: bleeding, hypersensitivity reactions, transaminitis, Heparin induced thrombocytopenia

Question 12

Heparin indications

Answer 12

used to prevent clot formation in various disorders:
DVT
PE
Dialysis machines
Atrial fibrillation
Myocardial infarction
Arterial or venous thrombosis

Question 13

Heparin induced thrombocytopenia (HIT)

Answer 13

Creates a pro-thrombotic state (associated with a high frequency of thrombosis)
Antibodies bind: Platelet factor 4, heparin and platelets
Platelets are activated and destroyed

Occurs 4-5 days after initiation of therapy

Question 14

LMWH has multiple advantages over UFH including

Answer 14

given subcutaneously once or twice daily w/o need for labs for daily monitoring

Lower risk of heparin induced thrombocytopenia

Safer then UFH for extended administration

Question 15

LMWH mechanism of action

Answer 15

Inhibits Xa and accelerates antithrombin III
Indirect thrombin inhibitor
LMWH more strongly inhibits Xa then UFH

Question 16

Aspirin

Answer 16

Acetylsalicylic acid (ASA)
Irreversible platelet inhibitor
Prevents the formation of clots by inhibition of the platelet plug
Rapid absorption with peak effects in 1 hr

Question 17

Primary prevention of CVA/MI with Aspirin

Answer 17

81 mg daily

Question 18

Secondary prevention of CVA/MI with Aspirin

Answer 18

Depends on the other meds

Acutely 325mg daily for MI and CVA

Question 19

Acute coronary syndrome with Aspirin

Answer 19

325mg chewed X 1

Question 20

Fibrinolytics (tPA, Streptokinase, Urokinase)

Answer 20

Convert plasminogen to plasmin to breakdown the fibrin strands

Question 21

Fibrinolytics Indications

Answer 21

For treatment of existing clots 
MI
Stroke
Massive PE
Limb threatening ischemia