Pharmacologic Treatment of Coagulopathies Flashcards

1
Q

What do Anticoagulants do?

A

inhibit the action or formation of clotting factors

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2
Q

Name some Oral Anticoagulants

A

Warfarin (Coumadin, Jantoven)
Dabigatran (Pradaxa)
Apixaban (Eliquis)
Rivaroxaban (Xarelto)

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3
Q

Describe Warfarin (Coumadin)

A

is the most widely used oral anticoagulant.
Mechanism of action: Inhibition of vitamin K dependent coagulation factors II, VII, IX, X
Also inhibits Protein C and S

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4
Q

How long does it take for Warfarin to reach therapeutic effect

A

36-72 hours

Normal clotting factors need to clear from the circulation

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5
Q

What is Warfarin used for?

A

to prevent further clot formation.

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6
Q

Indications for use of Warfarin

A
Venous and arterial thromboembolism
Pulmonary embolus
Stroke prevention in atrial fibrillation
Thrombus prevention in cardiac valve replacement
Stroke
Transient ischemic attacks
Prevention of clots
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7
Q

Dosing is based on what?

A

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

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8
Q

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

A

3rd day

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9
Q

What level should we start dosing Warfarin?

A

5 mg nightly

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10
Q

What things can dosing be dependent on?

A

Chronic dose will vary depending on the patient and their other medications
Chronic dose will also vary depending on the patient’s genotype
Adjust dose as need to achieve desired INR

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11
Q

What drugs can interact with Warfarin?

A

Just assume that EVERY drug interacts with warfarin - LOOK IT UP JACKASS!!!
Major interactions: cholesterol lowering meds (statins), most antibiotics, NSAIDs, drugs cleared through the liver

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12
Q

Food interactions that can decrease the INR

A

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

Smoking/tobacco decreases INR

Alcohol increases the INR

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13
Q

Purple Toe Syndrome

A

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

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14
Q

Treatment of Purple Toe Syndrome

A

stop the coumadin and switch to another anticoagulant.

Same treatment for skin necrosis.

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15
Q

Management of an elevated INR

A
No bleeding and INR < 5
-Hold warfarin
Bleeding or INR > 5
-Hold warfarin
-Oral or IV or subQ vitamin K
Life threatening bleeding
-Vitamin K
-Factor VII
-Fresh frozen plasma or Prothrombin concentrate
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16
Q

Dosing patients on Warfarin with vitamin K, How and when is it dosed?

A

Sub Q variable
IV 1-2 hours later give slowly or they DIE!
Oral 24-48 hours later
Avoid IM
Note:: affects warfarin for up to a week after administration

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17
Q

Patient education needs to include

A

indication, dosing, monitoring, side effects, drug interactions, diet, alcohol, birth defects if appropriate

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18
Q

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

A

2-3 days

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19
Q

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

A

5 days

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20
Q

Name 2 reasons it might be best to take this medication at night.

A

Not as much food reaction, For adjusting doses

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21
Q

Why is bridging with heparin important for initiation of therapy and for patients that may need procedures?

A

As a procoagulant state, to avoid necrosis. Patients with abnormal heart rhythm and a clot

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22
Q

Newer oral anticoagulants

A

Dabigatran (Pradaxa)
Rivaroxaban (Xarelto)
Apixaban (Eliquis)
Dont have to check INR

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23
Q

Major pros of new oral anticoagulants as compared to warfarin

A

No need for routine lab monitoring
Not affected by foods
Not as many drug interactions

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24
Q

Major cons of new oral anticoagulants as compared to warfarin

A

No antidote
No way to monitor anticoagulation
Dose adjustments likely needed for renal patients
Not for use in valvular heart disease

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25
Q

Parenteral Anticoagulants

A
Unfractionated IV heparin
	Heparin
Low-Molecular weight heparin
	Enoxaparin (Lovenox)
	Dalteparin (Fragmin)
	Fondaparinux (Arixtra)
26
Q

How do you monitor Heparin

A

PTT

27
Q

How do you monitor Warfarin

A

PT/INR

28
Q

Heparin mechanism of action

A

Potentiation of the action of antithrombin III and inactivating thrombin, IX, X, XI, XII, and plasmin
Prevents the conversion of fibrinogen to fibrin

29
Q

Unfractionated Heparin is used to prevent clot formation in what disorders?

A
DVT
PE
Dialysis machines
Atrial fibrillation
Myocardial infarction
Arterial or venous throbosis
30
Q

Contraindications and complications of Heparin

A

Contraindications: anaphylaxis and recent major surgery

Adverse effects: bleeding, hypersensitivity reactions, transaminitis(elevated liver enzymes), Heparin induced thrombocytopenia

31
Q

Antidote available to reverse in the case of severe bleeding/overdose

A

Protamine sulfate to rapidly reverse heparin
Slow IV infusion needed to prevent anaphylactic reaction
Can be used for LMWH and UFH

32
Q

Heparin Induced Thrombocytopenia

A

Can occur with unfractionated heparin and low molecular weight heparin
Most likely to occur with UFH

33
Q

Characteristics of terrible patients for chronic anticoagulants

A
Increased fall risk
Dementia
Occupational Hazard
Non-compliant patients
History of Aneurysm
Alcoholism
PUD
Old people
Liver Disease
Pregnancy
34
Q

Diagnostic evaluation

A
Noted when platelets drop by 50% after initiation of therapy
Platelet factor 4 antibody (PF4)
Not specific but sensitive
Serotonin release assay
Specific and sensitive
CBC, PLT, Urine for blood,
35
Q

Complication of Heparin

A

Heparin induced thrombocytopenia (HIT)

36
Q

Describe HIT

A

Creates a pro-thrombotic state
Antibodies bind: Platelet factor 4, heparin and platelets
Platelets are activated and destroyed

Occurs 4-5 days after initiation of therapy

37
Q

Treatment of HIT

A

Stop Heparin
Give alternative anticoagulant (direct thrombin inhibitor)
No platelet transfusions
Do not give warfarin until platelet count increases

38
Q

Direct thrombin inhibitors

A

Lepirudin,
Bivalirudin,
Hiruden,
Argatroban

39
Q

Low Molecular Weight Heparin

A

Enoxaparin (Lovenox),
Dalteparin (Fragmin),
Fondaparinux (Arixtra)

40
Q

LMWH has multiple advantages over UFH

A

Can be given subcutaneously once or twice daily without need for labs for daily monitoring
Lower risk of heparin induced thrombocytopenia
Home administration
Safer then UFH for extended administration

41
Q

LMWH mechanism of action

A

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

42
Q

Dosing LMWH

A

Once or twice daily administration
Time to effect is about 2 hours (SQ) with peak effect at 4 hours
Monitor drug concentration with lab for anti-Xa activity in those who are obese, pregnant or with poor renal function

43
Q

What would be the advantages of IV over SubQ?

A

Speed

44
Q

What do Antiplatelet drugs do?

A

inhibit platelet aggregation and prevent platelet plugs.

45
Q

Name some Antiplatelet meds

A

Aspirin
P2Y12 antagonists
Clopidrogrel (Plavix), Prasugrel (Effient), Ticagrelor (Brilinta)
Dipyridamole
Used in combo with aspirin (Aggrenox)
GIIb/IIIa antagonists
Abiciximab (Reopro), Eptifibatide (Integrelin)

46
Q

What does Aspirin do?

A

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

47
Q

Aspirin Dosing recommendations

A
Primary prevention of CVA/MI 
81 mg daily
Secondary prevention of CVA/MI
Depends on the other meds
Acutely 325mg daily for MI and CVA
Acute coronary syndrome
325mg chewed X 1
48
Q

What useful for those at risk for thromboemolism

A

Aspirin in addition to the primary and secondary prevention of CAD and MI

49
Q

Major side effect of Aspirin

A

Bleeding

50
Q

Other side effects of Aspirin

A

Always assess for GI bleeding
H2 blockers and proton pump inhibitors may decrease gastritis and GI bleeding
Administer with food to decrease GI disturbance
Tinnitus at higher doses
Resistance
Allergy

51
Q

What is Clopidogrel (Plavix) and the other P2Y12 antagonists used for?

A

Treatment and prevention of acute coronary syndrome

Treatment and prevention of thromboembolic events

52
Q

Irreversible inhibition of activation and aggregation is noted with which anticoagulants

A

Clopidogrel (Plavix)
-P450 system
Prasugrel (Effient)
Ticagrelor (Brilinta)

53
Q

Adverse effects of plavix

A

Bleeding
Multiple drug interactions with Plavix

Stop 7 days prior to surgery

54
Q

Dipyridamole

A

Secondary prevention in patients following stroke and TIA

Used often with aspirin in a single combination pill (Aggrenox)

55
Q

What is the MOA of Dipyridamole

A

it inhibits ADP and phosphodiasterase

56
Q

Dipyridamole causes what?

A

vasodilation and inhibit platelet aggregation

57
Q

Abciximab (Reopro) and Eptifibatide (Integrelin) side effects

A

Bleeding
Thrombocytopenia
Allergy

58
Q

Name some Fibrinolytics

A

tPA, Streptokinase, Urokinase

59
Q

What do Fibrinolitics do

A

break down existing clots.

Convert plasminogen to plasmin to breakdown the fibrin strands

60
Q

Indications for Fibrinolitics

A

For treatment of existing clots

  • MI
  • Stroke
  • Massive PE
  • Limb threatening ischemia
61
Q

Side effects of thrombolytics

A

life threatening bleeding.