Term
Enaparoxin (lovenox), dalteparin (fragmin), danaparoid (orgaran), and fondaparinux (arixtra) are all low molecular weight heparins.
How does the size and protein binding compare to regular heparin, and how does this affect the drug?
What is the predominant action of LMW heparin? |
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Definition
They are about 1/3 the size of heparin, and not highly protein bound, resulting in a more predictable anticoagulant effect.
Their action is predominantly the inhibition of factor Xa. |
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Term
| How do LMW heparins affect ACT and aPTT? |
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Definition
| They are NOT affected, and are not monitored. |
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Term
| LMWH and regional: when is it safe? |
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Definition
If on pre-op for prophylactic dosing, wait at least 10-12 hours after last dose prior to doing regional. If it's therapeutic dosing, wait at least 24 hours.
Post-op, if twice daily dosing is to be used, wait at least 24 hours before starting. If once daily dosing is to be used, wait at least 6 hours before initiating LMWH therapy, and 24 hours for the subsequent dose.
If a bloody tap occurred, wait at least 24 hours to start LMWH. Epidural catheters should be removed 2 hours prior to first dose of LMWH, or at least 10 hours after a dose, and subsequent dosing should not occur for at least 2 hours. |
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Term
Should surgery be delayed if a patient is on LMWH? If so, how long?
Is there any way to reverse it? |
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Definition
Should be delayed 12 hours after last dose.
If emergency: protamine neutralized 65% of anti Xa of LMWH. |
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Term
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Definition
| Inhibits vitamin K epoxide reductase which converts vitamin K epoxide to vitamin K, decreasing vitamin K levels. Thus, the coagulation proteins that need vitamin K are formed, but defected (factors II, VII, IX, and X, right Sam??) |
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Term
| How does coumadin affect platelets? |
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Definition
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Term
| The therapeutic effect of coumadin occurs when coagulation factors are reduced by how much? What is a therapeutic INR? |
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Definition
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Term
| Coumadin is a racemic mixture of 2 active isomers (r and s). S-warfarin is how much more potent? |
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Definition
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Term
We look at the PT and INR when someone is on coumadin. What clotting factors affect the PT?
So why do we use the INR? |
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Definition
PT--sensitive to factors II, VII, and X.
The INR is used to allow for standardized reporting of warfarin levels. |
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Term
Is coumadin acidic or alkaline?
Why should it be taken on an empty stomach?
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Definition
Acidic
Food slows the absorption |
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Term
How long does it take coumadin to peak?
What is the duration of action? Can I hold a dose to help restore PT to a therapeutic level?
What is the elimination 1/2 life? |
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Definition
About 1 hour
Duration is 2-5 days (half-life 24-36 hours!), so no, holding a dose is not going to be enough. |
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Term
Is coumadin highly protein bound?
What about a baby-momma--will coumadin cross the placenta? Breast milk?
How is it excreted? |
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Definition
Yuppers, 99%
Will cross the placenta (and cause serious fetal effects), does not cross into the breast milk
Excreted into bile and urine |
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Term
| What is the effect of chronic alcohol use on coagulation proteins? Is this a good thing with coumadin? |
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Definition
| Alcohol decreases the production of coag factors, as does coumadin, so together thing might get ugly. |
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Term
| We know that peeps on coumadin shouldn't eat their leafy greens (or other foods rich in vitamin K), but are there drugs we should be careful with? |
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Definition
Other highly protein bound drugs, such as cimetadine, phenylbutazone, or amiodarone.
Also, other anticoagulants have a synergistic effect, and should only be used with coumadin if they are closely monitored. |
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