Lecture Anticoagulants

Question 1

aggregation of platelets on arterial walls

Answer 1

arterial thrombi

Question 2

stagnated blood

Answer 2

venous thrombi

Question 3

anticoagulants

Answer 3

Inhibit synthesis or activity of clotting factors

venous thrombosis

Heparin
LMW Heparins (enoxaparin, dalteparin, tinzaparin)
fondaparinux
Warfarin
Direct Thrombin Inhibitors (dabigatran, argatroban, bivalrudin, desirudin)
Direct Factor Xa Inhibitors - rivaroxaban, apixaban)
Anticoagulants Antithrombin - rHat and Thrombate III

Question 4

Antiplatelets

Answer 4

inhibit platelet aggregation

arterial thrombosis

aspirin
clopidogrel
GP IIb/IIIa receptor antagonists - abciximab, eptifibatide, tirofiban
others - dipyridamole, cilostazol

Question 5

thrombolytics

Answer 5

promote lysis of fibrin

clot busters!!!

alteplase [tPA]
tenecteplase
reteplase

Question 6

Heparin (unfractionated)

Answer 6

rapid acting - injection only (IV, SubQ)

used in hospitals for emergencies - PE, massive DVT, acute MI

safe for pregnancy

watch for HIT

monitor aPTT
normal 40 sec
Heparin 60-80 sec

antidote: protamine sulfate

Question 7

Adverse effects of heparin (unfractionated)

Answer 7

Bleeding,

heparin-induced (HIT) thrombocytopenia - leads to thromboembolism

spinal/epidural hematoma

Question 8

antidote for Heparin

Answer 8

protamine sulfate

slow IV infusion - ≤20mg/min or 50mg/10min

1 mg protamine for 100 units of heparin

Question 9

HIT (Heparin Induced Thrombocytopenia)

Answer 9

Complication of exposure to heparin caused by autoantibodies to heparin-platelet protein complexes.

Usually occurs after 4+ days of heparin therapy

What you will see: (either 1 of these!)
1. Thrombocytopenia: platelets < 150,000
Platelet count reduction >50% from baseline
2. Venous or arterial thrombosis

So what do we do with HIT?!?
1. Stop heparin 
2. alternative anticoagulant: 
argatroban, 
3. They should NEVER EVER receive heparin or a LMWH for LIFE….

Question 10

Low-Molecular-Weight (LMW) Heparins

Answer 10

enoxaparin [Fragmin], dalteparin [Lovenox], tinzaparin [Innohep]

Prevention of DVT post-operative (abdominal surgery, hip/knee replacement), Treat DVT, prevent ischemic complications (unstable angina, non-Q-wave MI, STEMI)

Monitor – none needed
Can be used at home

Sub-Q ->Dosing QD or BID
Longer ½ life than regular heparin

Adverse effects:

1. Bleeding,
2. HIT,
3. spinal/epidural hematoma

Question 11

antidote for LMW heparins (enoxaparin, dlateparin, tinzaparin)

Answer 11

protamine sulfate

slow IV infusion - ≤20mg/min or 50mg/10min

1 mg protamine for 100 units of heparin

Question 12

Epidural or spinal hematomas may occur in patients who are anticoagulated with (3) and are receiving neuraxial anesthesia or undergoing spinal puncture.

Answer 12

low molecular weight heparins, heparinoids, or fondaparinux

These hematomas may result in long-term or permanent paralysis. Consider these risks when scheduling patients for spinal procedures.

Check their back!!!

Question 13

Warfarin

Answer 13

slow onset (8-12 hours for response); 1/2 life is 1.5-2 days

PO

used for long term prophylaxis of thrombosis (VTE, thromboembolism from prosthetic heart valves, Afib, etc)

NO pregnancy

monitor PT/INR
normal 1
warfarin 2-3

antidote: vit K
Note: tell pt to eat the same amount of Vit K in diet

Question 14

Warfarin toxicity

Answer 14

Vitamin K1 (phytonadione)
PO (2.5mg) – nonemergency
IV (0.5-1mg, diluted & infused slowly) – emergency

FFP (Fresh frozen plasma)
a blood product made from the liquid portion of whole blood.
It is used to treat conditions in which there are low blood clotting factors (INR > 1.5) or low levels of other blood proteins.

Question 15

aPTT

Answer 15

monitored for Heparin

normal 40 sec
Heparin 60-80 sec

Question 16

PT/INR

Answer 16

monitored for warfarin

normal 1
warfarin 2-3

Question 17

fondiparinux

Answer 17

Sub Q anticoagulant

Used for:

1. Prevention of DVT post-operative (abdominal surgery, hip/knee replacement),
2. Treat acute PE (with warfarin)
3. Treat DVT (with warfarin)

Adverse Effects:

1. Bleeding,
2. thrombocytopenia (not HIT),
3. spinal/epidural hematoma

Question 18

Anticoagulants used for Afib

Answer 18

warfarin
dabigatran etexilate
rivaroxaban
apixaban [Eliquis]