💊370: Anticoagulants Flashcards Preview

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Flashcards in 💊370: Anticoagulants Deck (37)
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1
Q

What is the mechanism of action of Heparin?

A

Stops clotting progression by suppressing fibrin formation

2
Q

What are dosing considerations for Heparin?

A
  1. Dosing by weight
  2. Can overlap with Warfarin
  3. Safe in pregnancy
3
Q

What are the two types of Heparin?

A
  1. Unfractionated Heparin (UFH)

2. Low Molecular Weight Heparin (LMWH)

4
Q

What is the mechanism of action of Unfractionated Heparin?

A
  1. Long chains bing to antithrombin, making more effective
  2. Impacts factor Xa, IX, XI, XII

Wraps around “hugs” thrombin

5
Q

What are side effects of UFH?

A
  1. Bleeding

2. Heparin-induced Thrombocytopenia (HIT)

6
Q

What is Heparin-induced Thrombocytopenia (HIT)?

A

Immune response leading to platelet activation and aggregation

  1. Platelet levels drop
  2. x30 risk Thrombosis

= Stop Heparin, use different anticoags (NOT LMWH)

7
Q

What should a nurse monitor for a patient on UFH?

A
  1. Hemoglobin, platelet counts
  2. Activated partial thromboplastin time (aPTT, goal 1.5-2x control)
  3. Nomagram
  4. Anti-Xa
8
Q

What is a prototype of Low Molecular Weight Heparin?

A

Dalteparin (Fragmin)

“-parin”

9
Q

What are advantages of LMWH?

A
  1. More predictable
  2. Less bleeding
  3. Less HIT
  4. No monitoring required
  5. Fixed dose schedule due to longer half life
  6. Easy to give as SC for outpatients
10
Q

What are disadvantages of LMWH?

A
  1. Drug price $$$
  2. Lower reversal of anticoagulation
  3. Dosing for renal/obesity uncertain
11
Q

What are side effects of LMWH?

A
  1. Bleeding
  2. HIT (Heparin-induced Thrombocytopenia)
  3. Spinal/epidural hematoma
  4. Antiplatelet drugs
12
Q

What is the mechanism of action of Fondaparinux (Arixtra)?

A

Small molecule, highly selective Xa inactivation

= similar to LMWH without HIT

13
Q

What are dosing considerations for Fondaparinux (Arixtra)?

A
  1. Safe in pregnancy
  2. Renal dose adjustment needed
  3. SC injection once daily
14
Q

What is the mechanism of action for Warfarin (Coumadin)?

A

Vitamin K antagonist - blocks synthesis of VII, IX, X, and prothrombin

15
Q

What are therapeutic uses for Warfarin (Coumadin)?

A
  1. VTE treatment and prophylaxis
  2. Thrombosis in artificial heart valves
  3. Stroke in AFib
  4. Recurrent TIA and MI
16
Q

What are side effects of Warfarin (Coumadin)?

A
  1. Bleeding
  2. Spinal/epidural hematoma
  3. UNSAFE for pregnancy and breastfeeding
  4. Liver disease, alcoholism

➡️ Vitamin K to reverse effects

17
Q

What are drug interactions with Warfarin?

A

*Highly protein bound

  1. CYP450 metabolized
  2. Increased bleeding with antiplatelets/acetaminophen/aspirin/Vitamin E
  3. Cholestyramine ⬇️ PO absorption
  4. Alcohol (liver)
  5. Gut bacteria - synthesize Vit K
18
Q

What are therapeutic uses for for Direct Oral Anticoagulants (DOACs)?

A
  1. Stroke (AFib)

2. VTE prophylaxis (ortho surgery)

19
Q

What are side effects of DOACs?

A
  1. Bleeding

2. Renal dysfunction (GFR < 30mL/min)

20
Q

What are drug interactions with DOACs?

A

P-glycoprotein (P-gp) pumps out DOACs in gut ➡️ Drugs inhibit P-gp
= azoles, verapamil, protease inhibitors

Anti platelets ⬆️ bleeding risk

21
Q

What are prototypes of Direct Thrombin inhibitors?

A

Dabigatran Etexilate (Pradax)

22
Q

What is the antidote to Dabigatran?

A

Idarucizumab

23
Q

What are side effects of Dabigatran?

A
  1. Dysplesia/gastritis

Take with food, antacids/PPIs

24
Q

What is a prototype of Direct Factor Xa inhibitors?

A

Rivaroxaban (Xaralto)

“-aban”

=Metabolized by CYP450

25
Q

What is the mechanism of action for Low Dose Aspirin (ASA)?

A

Suppress platelet aggregation by irreversible inhibition of COX enzyme

Effects persist for platelet lifespan (7-10 days)

26
Q

What is the dose of ASA for acute MIs?

A

160mg - 325mg

27
Q

What are side effects of ASA?

A
  1. Bleeding

2. GI upset/irritation (use enteric-coated ASA, ECASA)

28
Q

What is the mechanism of action of Clopidogrel (Plavix)?

A

Prodrug
Irreversible blockade of ADP Receptor on platelets
= prevention of platelet aggregation

29
Q

What are the therapeutic uses for Clopidogrel (Plavix)?

A
  1. Coronary stenting
  2. Stroke prophylaxis
  3. MI and other vascular event prophylaxis
30
Q

What are drug interactions with Clopidogrel (Plavix)?

A
  1. Bleeding

2. Proton Pump inhibitors (PPIs, omeprazole) ⬇️ efficacy

31
Q

What are side effects of Clopidogrel (Plavix)?

A
  1. Bleeding
  2. GI (pain, dyspepsia, diarrhea, n/v)
  3. Rash
  4. Headache
32
Q

What is a prototype of Thrombolytics?

A

Alteplade (tPA)

“-plase”

33
Q

What is the mechanism of action for Thrombolytics?

A

Increased conversion of plasminogen to plasmin, which then digests fibrin clots and degraded fibrinogen + clotting factors

  1. Short half life (5min)
  2. Rapid hepatic inactivation
34
Q

What are the therapeutic uses for Thrombolytics?

A
  1. Ischemic stroke
  2. Pulmonary embolism
  3. Acute MI
35
Q

What are side effects of Thrombolytics?

A

High risk of bleeding

= injections/wounds/procedures contraindicated

36
Q

What are contraindications for Thrombolytics?

A
  1. Prior intracranial hemorrhage
  2. Cerebro vascular lesión
  3. Ischemic stroke
  4. Internal bleeding
  5. Intracranial neoplasm
  6. Aortic dissection
  7. Sever HTN
37
Q

What is the mechanism of action for Alteplase?

A

tPA = tissue plasminogen activator

Conversion of plasminogen to plasmin ➡️ digests fibrin meshwork, degrades fribunigen ajd clotting Factors