Anticoagulants

Question 1

warfarin MOA

Answer 1

Inhibits synthesis of vitamin K–dependent clotting factors X, IX, VII, and II (prothrombin)

Question 2

Direct Oral Anticoagulants (DOACs) [formerNovel Oral Anticoagulants (NOACs)] MOA

Answer 2

Factor Xa inhibitor:
◦ Rivaroxaban (Xarelto)
◦ Apixaban (Eliquis)
◦ Endoxaban (Savaysa)
◦ Betrixaban (Bevyxxa)

Question 3

Direct Thrombin Inhibitor examples

Answer 3

◦ Dabigatran Etexilate (Pradaxa)
◦ Parenteral available also: bivalirudin (Angiomax), argatroban (Argatra, Novastatin, Arganova, Exembol), desirudin (Iprivask, Revasc)

Question 4

Heparin MOA

Answer 4

◦ Binds with antithrombin III

◦ Inactivates factors IXa, Xa, XIIa, XIII

Question 5

LMWH MOA

Answer 5

Low-molecular-weight heparin (LMWH)
◦ Regular heparin is processed into smaller molecules
◦ Enoxaparin (Lovenox), dalteparin (Fragmin), fondaparibnux (Arixtra), tinzaparin (Innohep)
◦ Inactivates factor Xa

Question 6

Fondaparinux (Arixta) MOA

Answer 6

◦ Selective inhibitor of antithrombin III and factor Xa inhibitor

Question 7

Benefit of LMWH

Answer 7

less monitoring

Question 8

Warfarin pharmacokinetics

Answer 8

◦ Well absorbed when taken orally
◦ Metabolized by CYP1A2 and 2C9
◦ Half-life of 3 to 4 days*
◦ Duration of effect 2-5 days

Question 9

Warfarin precautions and contraindications

Answer 9

◦ Pregnancy category X
◦ Use cautiously in patients with fall risk, dementia, or uncontrolled hypertension
◦ Avoid in hypermetabolic state
◦ Do not use as only anticoagulant if patient has documented protein C or S deficiency

Question 10

Warfarin will not

Answer 10

take effect right away. you will also have t to wait a while to see effects from a dose change

Question 11

There are a lot of ___ ___ with warfarin

Answer 11

drug interactions

Question 12

Protien C or S is

Answer 12

active within the clotting cascade. If you take with warfarin it may make clotting worse or cause skin necrosis

Question 13

Warfarin 2nd line for

Answer 13

VTE

Question 14

Warfarin treatment for

Answer 14

DVT and PE

Question 15

Warfarin dose to maintain

Answer 15

INR between 2 and 3

Question 16

Increase warfarin dose in

Answer 16

small increments (5-20% of total weekly doses)

Question 17

Warfarin Monitoring

Answer 17

◦ INR daily until in therapeutic range for 2 consecutive days, Then two or three times weekly for 1 - 2
weeks

◦ Then less frequently but at least every 6 weeks

Question 18

Warfarin ADR

Answer 18

Adverse drug reactions (ADRs)
◦ Bleeding
◦ Allergic reactions

Question 19

Warfarin atnidote

Answer 19

◦ Antidote is vitamin K

Question 20

Warfarin common drug interacions

Answer 20

◦ Many drug–drug interactions
◦ Drug-Herbal interactions: Ginseng, Ginko
◦ Drug-Food interactions: Cranberry, grapefruit, greens
◦ Antiplatelet drugs: NSAIDs, ASA
◦ Thrombolytic drugs

Question 21

Orthopedic surgery (total hip, knee replacement, hip fracture)
Trauma surgery - INR Range

Answer 21

INR 1.8-2.2

Question 22

VTE, a-fib, valvular heart disease, tissue valves

A-fib: CHA2dS2VASc score - INR Range

Answer 22

INR 2.0 – 3.0

Question 23

Mechanical, prosthetic heart valve replacement - INR Range

Answer 23

INR 2.5 – 3.5*

Question 24

Greens are rich in

Answer 24

Vit K

Question 25

Thrombophilia, thromboembolic event (Factor V Leiden, antiphospholipid syndrome, Protein C, S or Antithrombin deficiency) - INR Range

Answer 25

2 to 3

Question 26

Critical Value for INR

Answer 26

5.5

Question 27

Endogenous factors that will lead to decrease in INR

Answer 27

``` Edema Coumadin resistance Hyperlipidemia Hypothyroidism Nephrotic syndrome ```

Question 28

Exogenous facotrs that willd ecrease INR

Answer 28

``` Diet hi in Vit K Drug interactions Travel Unreliable INR ```

Question 29

other risk factors for decrease in INR

Answer 29

Malabsorption Medication dosing error Pt compliance

Question 30

alcohol abuse will increase risk for

Answer 30

major bleeding while taking anticoagulants

Question 31

Actions to take if elevated INR depends on

Answer 31

◦ Clinical severity of bleeding, rate of hemorrhage, and the location ◦ Extent to which INR is elevated ◦ Expected duration of therapy ◦ Initial indication for therapy

Question 32

Consider this when you have an elevated IRN

Answer 32

◦ Dietary changes ◦ Other medications, drugs, herbals ◦ Dose

Question 33

Treatment for: INR>therapeutic but <5, no evidence of bleed, rapid reversal for reasons of surgical intervention not indicated

Answer 33

Lower dose or omit next 1-2 doses of warfarin and then resume at lower dose when INR approaches therapeutic range. Daily INRs

Question 34

Treatment for: INR>5, <10 and pt is not bleeding (2 options for treatment)

Answer 34

1. Omit next 1-2 doses, monitor INR and resume at lower dose when INR in therapeutic range. Daily INRs 2. If pt at increased risk for bleeding, omit next dose and administer vitamin K 1-2.5mg orally

Question 35

If more rapid reversal required (e.g. surgery)

Answer 35

Vitamin K 3-5mg(o). Give 1-2mg(o) in 24h if still elevated

Question 36

Treatment for INR >10 and pt is not pleeding

Answer 36

Hold warfarin. Vitamin K 3-5mg (o). This should reduce INR in 24-48 hours. Recheck INR, if still elevated, may repeat Vitamin K Serious bleeding: Vitamin K 10mg IV; FFP; Prothrombin complex concentrate (PCC)

Question 37

Generic warfarin vs. coumadin - consideration

Answer 37

◦ Avoid alternating | ◦ Monitor INR more frequently if changing

Question 38

dental procedures with coumadin

Answer 38

◦ Cessation of coumadin for surgical and nonsurgical dental procedures may pose greater risk of thrombotic events than hemorrhagic events

Question 39

Consider lower coumadin dose if:

Answer 39

``` ◦ Older than 65-75 years ◦ Multiple comorbid conditions ◦ Poor nutrition ◦ Elevated liver enzymes ◦ Changing thyroid status ◦ Elevated INR when off warfarin ```

Question 40

Surgeon/dentist should be notified of

Answer 40

coumadin therapy prior to procedure

Question 41

Consider these questions regarding surgery

Answer 41

◦ Based on procedure, what is risk of bleeding associated with anticoagulation? ◦ If anticoagulation therapy is temporarily stopped, what is the risk of thromboembolism? ◦ Is the thromboembolic risk of stopping warfarin sufficient to warrant cross-coverage with UH or LMWH?