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what family do heparins belong to?
endogenoussubstances known as glycosaminoglycans (GAGs)
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Low molecular wt heparins:
- Reviparin
- Enoxaparin
- Dalteparin
- Tinzaparin
- Nadroparin
- Certoparin
- Parnaparin
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Pentasaccharides:
Fondaparinux
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MOA of heparins:
- Produce anticoagulation by amplifying Antithrombin III which inhibits factors IIa and Xa
- Increases antithrombin III
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kinetics of heparins:
- Very complex pharmacokinetics
- There is a large range in molecular weight of the molecules
- Binds to a lot of proteins (like albumin)
- The dose-response curve is difficult to predict·
- Dose must be individualized in every patient
- Titrated according to the activated partial thromboplastin time [aPTT]
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what is the general therapeutic aPTT range? on exam know this!
45-75 seconds (1.5-2.5x control)
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if aPTT is < 35:
- INCREASE DOSE!
- Increase infusion rate by 4 International Units/kg/hour and rebolus with 80 International Units/kg IV
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If aPTT is > 90:
- DECREASE DOSE!
- Hold infusion for 1 hour and decrease rate 3 International Units/kg/hour.
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indications for heparin:
- Treatment and prevention of inappropriate thrombosis·
- Venous thrombosis (PE) caused by: Stasis, Endothelial damage, Hypercoagulable states
- Arterial thrombosis
- initial mgment of: MI, unstable angina, coronary angioplasty or stent placement, cardiac surgery
- Disseminated intravascular coagulation (DIC)
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UFH: which administration has immediate onset of action?
that you would use when treating DVT...
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UFH: which administration has onset that occurs in 60 minutes?
use when trying to prevent DVT...
subQ
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what do you use to measure activity?
to monitor low molecular wt heparins
- Anti-Factor Xa levels
- aPTT is NOT USED to measure!!
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compared to UFR, LMWH has:
- longer half-life than heparin
- more predictable kinetic profile
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indication for UFH:
thromboembolism (prophylaxis)
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dose for UFH:
5000 units SC bid q 12 hrs
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what is the bridge therapy?
- bridge warfarin with heparin bc it takes 4-5 days for warfarin to have effects
- heparin can be d/c on day 5-6 (pts c/ massive PE or severe thrombosis should be off
- ered a longer period of heparin- ab 10 days)
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main SE c/ heparin:
- Heparin-induced Thrombocytopenia syndrome (HITS)
- HAT- heparin assoc thrombo
- Antibodies against platelet factor 4 are produced and bind to platelets
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What is the typical prophylatic for (Lovanox) eroxaparin?
- 40 mg SC once daily
- on exam
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VTE treatment with Enoxaparin?
- 1 mg/kg SC every 12 hours.
- With a 70 kg person:70 mg SC q 12 hrs
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what can be used in the management of patients with heparin-induced thrombocytopenia (HIT)?
Danaparoid
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CI for heparins?
- previous HITS
- coagulopathies
- active bleeding
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SE for heparins:
- osteoporosis
- hemorrhage
- hyperkalemia
- fever
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how can you reverse the hemorrhage?
with Protamine sulfate
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does LMWH have an antidote?
no
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which is safe to use in pregnancy-
heparin or warfarin??
- Heparin!!
- warfarin is teratogenic!!!!
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compared to UFH, LMWH--
1. do not _________ aPTT
2. more ________ kinetic profile
3. how are they more convenient?
- 1. prolong
- 2. predictable
- 3. more stable administration and less rigorous monitoring
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