Chapter 34: Anticoagulation Flashcards
Coagulation involves activation of ____ & the clotting cascade
Platelets
All of the clotting factors have an inactive and active form. Once activated, a clotting factor will activate the next clotting factor in the sequence until ___ is formed
fibrin
Which drugs are direct factor Xa inhibitors
rivaroXAban
apiXAban
edoXAban
betriXAban
Which drug is an indirect factor Xa inhibitor
Fondaparinux
Which drugs are IV direct thrombin inhibitors & which drug is an oral direct thrombin inhibitor
IV - arbatroban, bivalirudin
PO- dabigatran
What are the major differences between warfarin and DOACs
- DOACs = less DDI, less or comparable bleeding, and a shorter half-life compared to warfarin
- DOACs are dosed based on the indication and kidney/liver function while warfarin is dosed based on INR
- Use DOACs for stroke ppx in AFib if the CHA2DS2-VASc score is >/= 2 (men) or >/= 3 (women); BUT if there is moderate-severe mitral stenosis or mechanical heart valve, use WARFARIN
- Use DOACs for VTE treatment, BUT if the pt has cancer use LMWH
Primary organization that publishes guidelines for anticoagulation
American College of Chest Physicians (CHEST)
Warfarin drug class
Vitamin K antagonist
Vitamin K is required for the carboxylation (activation) of which clotting factors
II, VII, IX and X
2, 7, 9, 10
INR is affected by many drugs and changes in
dietary vitamin K
UFH, LMWH, and fondaparinux MOA
work by binding to antithrombin (AT)
which inactivates thrombin (factor IIa) and other proteases (like factor Xa)
involved in blood clotting & prevents the conversion of fibrinogen to fibrin
Direct thrombin inhibitors MOA
block thrombin directly (factor IIa),
decreasing the amount of fibrin available for clot formation
Why are the IV direct thrombin inhibitors (argatroban and bivalirudin) clinically important
They do not cross-react with HIT antibodies
What is the DOC once HIT develops in the hospital setting
IV argatroban
Dabigatran brand name
Pradaxa
Which organization requires policies and protocols to properly initiate and manage anticoagulant therapy
The Joint Commission’s National Patient Safety Goals
Which lab could signify that bleeding is occurring while on an anticoagulant
an acute drop in hemoglobin
Which drugs/conditions can cause bruising
Chronic steroids
thrombocytopenia/clotting disorder
Cushing’s syndrome
malnutrition, fracture/sprain, infection
Which drugs/conditions can cause a hematoma
on abdomen from LMWH injection that was rubbed (do not rub), or an epidural or spinal hematoma in a patient using LMWH or DOAC who is given neuraxial anesthesia or a spinal punture
What can an upper GI bleed present as
coffee-ground emesis (vomit) or dark and tarry-looking stools
Esophageal bleeding occurs from
varices (bleeding veins, with liver cirrhosis), chronic reflux (esophagitis, Barrett’s)
How does stomach bleeding occur
from ulcers (e.g., NSAID-induced)
How does duodenal bleeding occur
from ulcers (e.g., H. pylori-induced)
The farther the bleeding site is from the anus, the ___ (lighter/darker) the stool
darker
UFH prophylaxis of VTE dose
5000 units SC Q8-12H
UFH treatment of VTE dose
80 units/kg IV bolus; 18 units/kg/hr infusion
UFH treatment of ACS/STEMI dose
60 units/kg IV bolus; infuse 12 units/kg/hr
Which weight is used for dosing UFH & LMWH
TBW
UFH CI
uncontrolled active bleeding
UFH side effects
bleeding (epistaxis, ecchymosis, gingival, GI)
thrombocytopenia
HIT
alopecia
hyperkalemia
osteoporosis (with long-term use)
UFH monitoring
aPTT or anti-Xa level, platelets, Hgb, Hct
When should you check aPTT level while using UFH
6 hours after initiation and every 6 hours until therapeutic
What the the therapeutic range of aPTT
1.5-2.5 x control
A decrease in platelets > __% from baseline suggests HIT
50%
UFH antidote
protamine
Continuous IV infusions are common for treating VTE and ACS because heparin has
a very short half-life
What is HepFlush used for
to keep IV lines open
UFH warnings
Fatal medication errors, especially in neonates, occurred when the incorrect heparin strength (higher dose) was chosen
The anti-factor ___ activity in LMWH is much greater than the anti-factor __ activity
Xa
IIa
Enoxaparin ppx of VTE dose & dose if CrCl < 30 mL/min
- 30 mg SC Q12H or 40 mg SC daily
- CrCl < 30 mL/min: 30 mg SC daily
Enoxaparin treatment of VTE and UA/NSTEMI & dose if CrCl < 30 mL/min
1 mg/kg SC Q12H
(or 1.5 mg/kg SC daily only for inpatient VTE treatment)
-CrCl < 30 mL/min: 1 mg/kg SC daily
LMWH treatment for STEMI in patients:
< 75 years
CrCl < 30 mL/min
- 30 mg IV bolus plus a 1 mg/kg SC dose
- CrCl < 30 mL/min: 30 mg IV bolus plus a 1 mg/kg SC dose
LMWH treatment for STEMI in patients:
> 75 years
- > 75 years: NO bolus
- CrCl < 30 mL/min: 1 mg/kg SC daily
LMWH CI
Hx of HIT, active major bleed
LMWH side effects
Bleeding
anemia
injection site rxns (e.g., pain, bruising, hematomas)
↓ platelets
____ level monitoring is recommended in pregnancy with LMWH
Anti-Xa
Obtain peak anti-Xa levels __ hours post SC dose
4
LMWH antidote
protamine
T/F: the air bubble from LMWH syringe should be expelled
False (can cause loss of drug)
HIT is an immune-mediated __ drug reaction that has high risk of venous and arterial thrombosis.
IgG
If left untreated, HIT can lead to a ______ state causing many complications including heparin-induced thrombocytopenia and thrombosis (HITT). HITT leads to amputation, post-thrombotic syndrome and/or death.
prothrombic
How is a diagnosis of HIT made
an unexplained drop in platelet count
(>50% drop from baseline)
If a patient is on warfarin and diagnosed with HIT, what should be done
d/c the warfarin and administer Vitamin K
In patients with HIT, which anticoags are recommended
non-heparin anticoagulants (in particular, argatroban)
In a patient with HIT, warfarin should not be started until the platelets have recovered to
> /= 150,000/mm3
In patients with HIT, what is the preferred anticoag if urgent cardiac surgery or PCI is required
bivalirudin
Fondaparinux is a synthetic _____
pentasaccharide
Apixaban brand name
Eliquis