Exam 2: Hemostasis Flashcards

1
Q

UFH: MOA

A

binds to Antithrombin III, enhances action:

  • inhibits IIa and Xa (significant)
  • inhibits IXa, XIa, XIIa, XIIIa
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2
Q

Protamine: indications

A

reverse anticoag effects of heparin

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3
Q

Protamine: MOA

A

+ charge, basic

reverses heparin b/c heparin is - charge, acidic

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4
Q

LWMH: examples

A

enoxaparin*

dalteparin

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5
Q

LWMH: monitoring

A
  • minimal effect on clotting lab assays
  • antifactor Xa available (used for complicated conditions: CrCl <30, pregnancy, obesity)
  • baseline CBC w/ platelets
  • SCr
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6
Q

Fondaparinux: MOA

A

factor Xa inhibitor: synthetic pentasaccharide

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7
Q

Fondaparinux: indications

A

safe/effective alternative to LWMH for VTE (longer half life)

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8
Q

Fondaparinux: contraindications

A

CrCl <30 mL/min

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9
Q

Warfarin: indications

A

Afib: (as long as in afib)
DVT or PE:
-provoked: 3 months
-unprovoked: at least 3 months
-recurrent: indefinite (unless high bleed risk)
-DVT w/ cancer: LMWH 3-6 months, then long term warfarin
Prosthetic heart valves: indefinite
Bioprosthetic heart valves: 3 months (up to 1 year if prior embolism)

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10
Q

Warfarin: drug interactions causing increased INR

A
Amiodarone*
acute alcohol use
Cimetidine
Erythromycin
Fluconazole
Metronidazole
TMP-SMX
BS abx
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11
Q

Warfarin: drug interactions causing decreased INR

A
chronic alcohol use
Rifampin
Carbamazepine
Barbituates
Cholesyramine
Vitamin K
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12
Q

Warfarin: drug interactions that increase bleeding risk but do NOT affect INR

A
Aspirin
Clopidogrel
Ticlopidine
NSAIDs
Dipyridamole
Fish oil
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13
Q

Vitamin K Phytonadione: indications

A
  • INR > 10.0 even w/o evidence of bleeding

- any minor bleeding regardless of INR

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14
Q

Warfarin: monitoring

A
  • ADRs: skin necrosis, purple toe syndrome, bleeding
  • INR on day 3-4
  • INR on day 7
  • once INR is therapeutic for 2 visits 2 weeks apart, follow-ups every 4 weeks
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15
Q

Best choice for long term tx of VTE

A

DOACS OVER warfarin

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16
Q

Best choice for tx of VTE in pts w/ cancer

A

LWMH OVER DOACs and warfarin

17
Q

DOACs

A
dabigatran
rivaroxaban
apixaban
edoxaban
betrixaban
18
Q

DOAC: MOA (and the one exception)

A

direct factor Xa inhibitor, EXCEPT

dabigatran: competitive and reversible direct thrombin inhibitor

19
Q

Dabigatran: contraindications

A

VTE, if CrCl < 30
Afib, if CrCl < 15
*can’t use at all if CrCl < 15 mL/min

20
Q

Dabigatran: special consideration when starting

A

VTE tx requires 5-10 days of parenteral anticoag (UFH or LMWH) BEFORE initiation

21
Q

Dabigatran: ADRs

A
  • bleeding: increased risk in elderly (>75 y/o)

- indigestion and gastritis like syndromes

22
Q

Apixaban: contraindications

A

severe renal impairment

23
Q

Edoxaban: special considerations when starting

A

VTE tx requires 5-10 days of parenteral anticoag (UFH or LMWH) BEFORE initiation

24
Q

DOAC: contraindications

A
  • pregnancy/lactation
  • liver impairment
  • CrCl requirements
25
Q

DOAC: boxed warnings

A
  • spinal/epidural anesthesia or puncture risk (risk of hematoma)
  • premature discontinuation
26
Q

DOAC: appropriate INR at which to switch from warfarin to DOAC

A
Apixaban <2.0
Dabigatran <2.0
Edoxaban <2.5
Rivaroxaban <3.0
Betrixaban (no recommendation)
27
Q

DOAC: drug interaction

A

P-gp and strong CYP3A4 inhibitors

28
Q

DOAC: disadvantages

A

no reliable measurement assay
mgmt of severe bleeding?
short half life (esp. compared to warfarin)
$$$$$

29
Q

Dabigatran: emergent reversal

A
Idarucizumab (Prax-BIND)
activated charcoal
hemodialysis
prohemostatic agents:
-4F-PCC (Kcentra)
-aPCC
30
Q

Oral factor Xa inhibitors: emergent reversal

A

Adexanet alfa, for:
Apixaban
Rivaroxaban

activated charcoal
hemodialysis
prohemostatic agents:
-4F-PCC (Kcentra)
-aPCC
31
Q

Thombolytic agents: MOA

A
  • tissue plasminogen activators (t-PAs)

- preferentially activate plasminogen that is bound to fibrin

32
Q

Thombolytic agents

A

Alteplase (tPA/ rtPA)
Reteplase
Tenecteplase

33
Q

Thombolytic agents: indications

A

ACS: STEMI
ischemic stroke
>18 y/o
Sx onset <4.5 hours before tx

34
Q

Thombolytic agents: contraindications

A

NSTE ACS

anything that increases pt’s risk for bleeding (see slides)

35
Q

Thombolytic agents: reversal

A

d/c thrombolytic agent
blood replacement
Aminocaproic acid
Tranexamic acid

36
Q

Aminocaproic acid and Tranexamic acid: MOA

A
  • inhibit activation of plasminogen and inhibit plasmin binding to fibrin
  • (tranexamic acid more potent)
37
Q

Aspirin: MOA

A

irreversibly inhibits COX-1, decreasing platelet aggregation

38
Q

Thineopyridines

A
  • (group of antiplatelet drugs)
  • clopidrogrel
  • plasugrel
39
Q

Thienopyridines: MOA

A

inhibits platelet P2Y12 ADP receptor»> irreversible inhibition of platelet activation and aggregation