Therapeutics - VTE Part 2 Flashcards
LMWH can be used for VTE treatment for initial AND long term therapy
however, long term use is reserved for who?
pts who can’t take warfarin or have cancer
which is more predictable and why - heparin or LMWH
LMWH
less protein binding so better PK profile
it’s better clinically - less deaths and hemorrhages and recurrent VTE
true or false
clearance of LMWH is dependent on kidney function
TRUE
where is LMWH like enoxaparin injected
available as prefilled syringes or multi dose vials
injected into abdominal area aorund the belly button or the outer upper thigh
rotate injection sites!
how does the dose of enoxaparin change for kidney function
normal - 1mg/kg subq q 12 or 1,,5mg/kg subq qd
BUT if crcl less than 30 - do 1mg/kg qd
true or false
there is no kidney concern with dalteparin and tinzeparin
FALS
they are LMWH —- if cr cl less than 30, need to be cautious and consider reducing dose
how are dalteparin and tinzeparin administered
subq
true or false
it is not routine to monitor efficacy when treating VTE with LMWH
true
may check anti xa activity only in renal disease or pregnancy
BBW enoxaparin and LMWH
same as fondaparinux –spinal hematoma after lumbar puncture, epidural, etc
the AE of LMWH is similar to….
heparin
true or false
LMWH has a lower risk of developing osteoporosis than heparin
true
true or false
protamine can be used to reverse LMWH
FALSE
**cost of heparin vs LMWH
the drug itself — enoxaparin is more expensive BUT if getting heparin you need to stay in hospital - potential cost more – requires tubing and infusion pump and a nurse
whereas LMWH given once or twice a day by YOURSELF in prefilled syringes
**differentiate between the monitoring of LMWH vs heparin for treating VTE
heparin - have to monitor the aPTT frequently until reaches therapeutic range, and then monitor daily
LMWH - no monitoring necessary, only rare occassions
**differentiate between the reversal agent for heparin vs LMWH
heparin has protamine, LMWH does not have one
*differentiate between the half lives of LMWH vs heparin and is this is advantage/disadvantage
heparin has shorter half life. this is good bc we can turn it off if procedure or bleed is suspected, however it does need continuous drip
LMWH has longer half life which is bad bc we can’t quickly stop it, however, it can be administered once or twice at home
***true or false
LMWH has lower HIT and osteoporosis than heparin
true
can fondaparinux be reversed
no
checking for target aPTT for heparin is every….
6 hours! - thats a lott use nomogram to help!
differentiate between HIT type 1 and HIT type 2:
-immune mediated?
reversible?
occurs quickly or over 5-14 days?
platelet count?
symptoms?
MANAGEMENT?
HIT typ1 is non immune, reversible, platelets below 100k, occurs quick, and is asymptomatic. NO management needed
HIT typ 2 is immune mediated and has long onset, platelets decrease below 50% and there is high risk of clot. management is to stop the heparin, start a direct thrombin inhibitor, and document the allergy
there is higher risk of HIT type 2 when it is administered what route?
IV is higher risk than subq
also, heparin has higher risk than UFH
name 3 intravenous direct thrombin inhibitors
they are used as alternative anticoagulants in _____
argatroban, lepirudin, bivalirudin
HIT
bridging to warfarin with an IV direct thrombin inhibitor
it’s hard bc they all increase the INR
for which IV direct thrombin inhibitor do we reduce the dose for hepatic dysfuncion? what about renal?
renal - lepirudin and bivalirudin
hepatic - argatroban
3 reasons why bridging is necessary when we want to start warfarin to treat VTE
has longgggg half life. need to give parenteral anticoagulant first
need to get to the anticoagulated state quickly – cant wait long when the pt has a dangerous clot
clotting factors have a long half (last long time) and our endogenous anticoagulants have a short one! – pts are in hypercoaguable state
true or false
when using bridge therapy to treat VTE, warfarin is started on day 1 with the parenteral therapy
TRUE
parenteral is then continued for 5 or more days AND until the INR is 2 or more
monitoring for warfarin - how often:
-inpatient?
-outpatient?
-how is the dose calculated?
inpatient - daily
outpatient - every few days after first starting, then eventually every 4-6 weeks when the pt is stable
dose is calculated GENTLY - total weekly dose is increased or decreased by 10-15% depending on results
important note when monitoring iNR
it lags! takes days to see the effect
NORMAL aptt
around 25-30 secs
3 AE of warfarin
hemorrhge
skin necrosis (rare)
purple toe syndrome (rare)
the bleeding/hemorrhage risk for warfarin is strongly related to….
the INR value! need to watch very closely
how can rare skin necrosis from warfarin be avoided
by bridging with parenteral
if it happens tho - need to stop the warfarin
same w purple toe syndrome
large doses of vitamin K can cause….
prolonged resistance to warfarin
general management of overanticoagulation from warfarin
can give vitamin K, blood, cfresh frozen plasma, or factor concentrates (but short half life)
is vitamin K administered IM? sub q? iv? po?
IM - CONTRAINDICATED
subq - unrelaible absorption
IV - does correct the INR within 24 hours, but there’s potential for anaphylaxis — have to dilute and administer SLOW
PO - corrects the INR in 1-2 days
INR less than 5 what is recommendation
lower or hold the dose
INR is 5-8.9 what is recommendation
hold 1 or 2 doses of warfarin
can consider giving vitamin K less than 5mg PO
INR is 9 or more what is recommendation
hold the warfarin, and give vitamin K 5-10mg po
if the INR is so high OR there is serious bleeding, what is recommendation
hold warfarin, give vitamin K 10mg IV + factor replacement
when giving warfarin, it’s so important to counsel patients on what
many factors can affect the INR
-vitamin K intake
-ethanol will elevate
-diarrhea, hepatic disease, heart failure, etc
-genetics in CYP2C9 and VKOR
_________ is a contraindication to giving warfarin
NONADHERENCE
patient understanding and willingness to monitor are so necessary
true or false
all DOACs are renally eliminated
FALSE - all except apixaban
true or false
for DOACS, there is required, routine anticoagulation monitring
FALSE - not necessary
2 boxed warnings for DOACs
-spinal hematoma
0increased thrombotic events if early discontinuation
dabigatran can be used to treat VTE
explain place in therapy
there is NOT BRIDGE
given AFTER 5-10 days of parenteral therapy - NO OVERLAP
dabigatran dose for treating VTE
150mg PO BID
storage and expiration counseling pts dabigatran
store in ORIGINAL container (NO PILL BOXES) and expires 4 months after opening!
do you have to monitor the coagulation panel when using dabigatran to treat VTE
NO
may affect it, but not needed to adjust dose
reversal agent for dabigatran
idarucizumab (praxbind)
2 AE dabigatran
hemorrhage and GI events
true or false
xarelto can be used in bridge therapy to treat VTE
FALSE
used AFTER parenteral therapy
15mg BID for 3 weeks with food, then 20mg PO daily with food
true or false
xarelto is on the beers list
TRUE
avoid in older adults
dose eliquis
10mg PO BID for 7 days, then 5 mg PO
if using for extended therapy, 2.5mg PO BID
Xa inhibitor (ie - eliquis, xarelto) reversal agent
andexanet (andexxa)
bolus, then IV infusion but LOT of money
true or false
edoxaban is NOT part of bridged therapy
true
given AFTER 5-`0 days of parenteral therapy
differentiate between the monitoring for DOACs vs warfarin
DOACS need NO routine monitoring (tho the labs are affected if checked)
warfarin - need routine INR monitoring - that’s how you find dose!
true or false
for most doacs, there is no effective reversal agent available
true
true or false
for warfarin, there is no effective reversal agent available
FALSE - there is
vitamin K, frozen plasma, prothrombin complex concentrate
differentiate between the onset and elimination of DOACS vs warfarin
DOACS - quick onset and quick elimination
warfarin - long onset and long elimination – that’s why it needs bridge!!
differentiate between the DDI of DOACS and warfarin
DOACS - just some ddi
warfarin - HUNDRES of DDI
AE and efficacy of DOACs vs warfarin
both are relatively the same, except that apixaban has less bleeding concern
name a drug that is only used then PE is so severe that you need to clear ASAP
alteplase - a thrombolytic - ONLY given once
true or false
patients need to have consistent vitamin K intake for warfarin to work
true! dont change randomly tho - just take normal, recommended amount in your diet
