VTE Prophylaxis Flashcards
Prophylaxis goal?
Identify patient risk Determine risk level Select the correct regimen pharm and non pharm
Non pharm treatment Therapy for VTE
Graduated compression stockings (GCS) - good for low or moderate risk Can wear leg too big - IPC- intermittent pneumatic compression increase circulation
Pharmacologic Prophylaxis
Duration is unclear but once patient can ambulate or other RFs are gone then dc therapy - Knee replacement, treatment for 12 days after - Hip replacement 35 days after
Standard dosing for LMWH ?
Regardless of weight
Risk Level
- What are the goals for VTE treatment?
- Prevent short term complications within 6 months
- Prevent extension of clot
- Prevent embolism clot
- Prevent death
- Prevent extension of clot
- Prevent long term complications past 6 months
- Post thrombotic syndrome
- Pulmonary HTN
- Recurrent VTE
UFH is from?
Does what to clots?
From procine stomach or bovine lung
Does not dissove clot but prevents growth
Binds to AT
neutralizes Thrombin factors Xa IX, Xia, XIIa
UFH is administered?
Non specific binding site so?
IV and Sub Q
Sub Q onset is 1-2 hours
Poor bioavailability
It is critical to achieve ___ of UFH within the first?
What type of dosing is there?
therapeutic dose within 24 hours
Weight base
Standard dose
VTE chart
UFH requires close monitoring and is done by the lab test?
Activated partial thromboplastin time (aPTT)
Normal therapeutic range for aPTT?
___ to ___ the control aPTT value
28-42 seconds
1.5 to 2.5
Baseline aPTT is done?
6 hours after starting UFH infusion and 6 hours have dose change
Takes 6 hours to reach steady state
Adverse effects of UFH/
- Bleeding
- Thrombocytopenia
- HIT in 5%
- Long term use can casue Alopecia, Hyperkalemia, Osteoporosis
HIT
- Is an immune system clotting disorder
- Formation of abnormal antibodies cause platelet activation
- Monitor platelets every 2-3 days during UFH therapy
- If platelets fall below 50% from baseline or below 120000 think HIT
UFH antidote?
Protamine
UFH is ok to using in ___ patients
if patient is ____
Contraindication?
Pregnant
Can breastfeed
Contraindication is Hx of HIT
LMWH
Binds to Xa not much to do with thrombin
Advantages of LMWH?
- The anticoagulant response is more predictable less binding to plasma and cellular proteins
- Reduced need for monitoring
- Improved SUB Q bioavailability
- Longer half life
- Lower chance of HIT
- Lower chance of osteoporosis
LMWH products
Parin, Parin, Parain
Dalteparin
Enoxaparin
Tinzaparain
LMWH has much greater effect on ___
but a draw back is that there is no?
Xa activity
has no antidote
Priot to therapy of LMWH you should?
Dosing is strictly ____ based
Given ___ in ___
Baseline PT/INR, aPTT, CBC w/ platelet, serum creatinine
Weight based
QD or BID
Given Sub Q in the abdomen
AE of LMWH?
Contraindications?
- Bleeding
- Bruising
- HIT lower risk though
- Contraindicated if Hx of HIT or suspected HIT
Protamine can be used as an antidote for LMWH but it only neutralizes it by?
60%
LMWH is a great choice over UFH in patients that are?
pregnant
If it is an uncomplicated DVT most patients can treat from?
But the regimen must be?
This reduces?
From home
Strict regimen
Cost saving
Factor Xa inhibitors?
- Fandaparinux SUB Q
- Rivaroxaban
- Apixaban
- Edoxaban
Fondaparinux is indicated for?
- Prophylaxis of DVT in patients undergoing surgery
- Treatment of DVT or PE when administered with warfarin
Fondaparunix has a ___ onset
___ elminated no ___ metabolism
Long ___
rapid onset
renally eliminated no liver metabolism
long half life
AE of Fondaparinux?
If major bleeding?
Life threatening bleeding
- Bleeding, monitor CBC at baseline
- If major bleeding then
- Fresh frozen plasma
- Factor concentrates
- Life threatening bleed
- Factor VIIa super expensive
Rivaroxaban and Apixaban
Substrates of?
CYP3A4 and p-glycoprotein
Drugs that inhibit this increase levels significantly (Ketoconazole, ritonavir, clarithromycin)
Drugs that induce these may decrease levels (Carbamazepine, phenytoin, amiodarone, macrolides, diltiazem, rifampin, St johns)
Currently there is no ___ for Rivoraxaban and Apixaban
It is also very ___
Antidote
costly compared to warfarin
Edoxaban
Indicated for?
Cost compared to rivoroxaban?
Avoid what?
Treatment of DVT an PE
rifampin
Costs less than Rivo and APixa
Direct Thrombin Inhibitors?
What do they do?
- Bind directly to Thrombin and prevent
- Formation of fibrin
- positive feedback mechanism of thrombin
- Platelet activation
- Factor V, VIII, XI, XIII activation
- Anticoag independent of AT
- Able to inhibit circulation of clot bound thrombin
DTI drugs?
Rudin- SC injection and not indicated for HIT
Argatroban- IV
Dabigatran- PO
Advantages of using a DTI?
- Specific for thrombin
- Inactivate clot bounf thrombin
- No interaction with platelet factor 4 (PF4)
- Have not been assoiciated with osteoporosis
Desirudin is indicated for?
- Prevention of DVT in elective hip surgery
- SC admin
- Dose every 12 hours
- Renally eliminated
- Monitor with aPTT
Argatroban?
Admin?
Binds to?
Metabolized?
No effect if?
Monitor with?
Approved for the treatment of?
- Binds to thrombin
- IV
- Liver metabolism
- No effect if renally impaired
- Monitor with aPTT
Approved in the treatment of HIT
Dabigatran?
Treatmetn of?
Admin?
Metabolized?
Avoid use with?
Avoid p-gp inhibitors if CrCL
- Treatment of DVT and PE
- Prevention of DVT and PE in hip replacement therapy
- Metabolized by liver excreted by kindeys
- Avoid if CrCL < 30 mL/min
- Avoid use with P-gp inducers
- 50 mL/min
Dabigatran antidote?
Idarucizumab
IV infusion or bolus
DTIs AE
If major bleeding give?
- Bleeding is the most common side effect
- No antidate expect for Dabigatran
- Major bleeding give
- FFP
- Factor concetrates
- Prothrombin complex concentrates
- Recombinant factor VIIa
Warfarin is the ___ anticoagulant
Indicated for?
Oral anticoagulant
Prevention and treatment of VTE
Warfarin is a very effective drug but?
- Has a narrow therapeutic window
- Frequent dose admin
- Patient monitoring
- DIs
- Food interactions
Warfarin
____ if clotting factor already formed
___ anticoag delayed __ to ___ days
Potential for _________ state
No effect
Full 7 to 15 days
hypercoagulable state
Warfarin is highly
Hepatically metabolized by?
Highly protein bound (albumin)
Metabolized by CYP450 1A2, 2C9, 3A4
Warfarin does not follow linear kinetics
Individual dose determined by?
- Patients response
- Intensity of anticoagulation needed
- Diet
- D-D interactions
- health
Lots of monitoring
Warfarin
If pt is < 55 and healthy
Start at ___ mg daily ot less if patient is?
7.5 - 10
- >75
- CHF
- Liver failure
- Poor nutrition
- Taking interacting meds
- high risk of bleeding
International Normalized Ration or INR is?
- Standard practice for monitoring
- INR range 2 -3 for treatmetn and prevention of VTE (target is 2.5)
When starting warfarin INR should be monitored every for the 1st week?
Less frequent if?
Ask pt about?
2-3 days
- Weekly for 1-2 weeks
- monthly 4 weeks
- If stable INR test q 12 weeks
Ask pt about adherence, vit K food, EtOH, Health
Warfarin if VTE then ____ overlapped with warfarin?
rapid acting anticoagulant
minimum of 5 days
And stable INR >= 2
Adjust dose based on total weekly dose
If dose is adjusted then wait and recheck INR
Major adverse effect of warfarin is?
what else
High INR = ?
Instability and large fluctuations in INR?
Bleeding
DI bleeding ICH
Intensity of anticoagulant related to bleeding
higher bleeding risk
bleeding risk
Warfarin overdose can be corrected with?
Vit K
if not working use FFP and Clotting factor concentrates
INR 4.5 - 10
INR > 10
Hold 1-2 warfarin doses and decrease dose
Hold 1-2 doses and resume at lower dose
Vit K Foods?
Anything green, chick peas, tea
Patient education of warfarin?
- Compliance is key
- SE
- Dietary instructions
- Frequent INR monitoring
- Physical activity
- No prego
- Take at night
Recommened Duration of Long term anticoagulation
Risk factors for bleeding while taking Anti coags
