anticoagulation and anemia Flashcards
clotting factor Xarelto primarily works on
Factor Xa, Factor Xa is a key point in the coagulation cascade, known as the common pathway, because it’s where the intrinsic and extrinsic pathways converge.
Which labs need to be closely monitored when pt on heparin
aPTT, PLT count, Hgb, HCT, anti-Xa (more specific for heparin effect, used in pt with heparin resistance, pregnancy, liver disease, obesity)
Indications of use for TPA
Thrombotic stroke and MI
Which anticoag andexxa is used to counteract
Decoy for factor Xa inhibitors, Xarelto & Apixaban
MOA of aspirin
Blocks COX-1 receptors decreasing synthesis of thromboxane, decreasing platelet aggregation
Antiplatelet drugs that are ADP antagonists
non-thienopyridine ADP antagonist
Ticagrelor (brillinta) more expensive than plavix but easily reversible can cause SOB and bradycardia
Thienopyridine ADP antagonist
Clopidogrel (plavix) blocks ADP which causes platelet activation
Onset of action of warfarin
1.5-3 days
onset of action of xarelto
2-4 hours
onset of action of apixaban
3-4 hours
onset of action of pradaxa
1-3 hours
Which receptors anti-platelet activity of acetylsalicylic acid (ASA) works on
irreversibly inhibiting the COX-1 enzyme, which affects thromboxane A₂ production, Since aspirin causes irreversible inhibition, its antiplatelet effect lasts for the life of the platelet (7–10 days).
Which antiplatelet drugs are antagonists
Thienopyridine ADP antagonist: plavix
Non-thienopyridine ADP antagonist: brillinta
GP IIb/IIIa inhibitor: abciximab (Reopro)
Which anticoagulant for afib is recommended when gfr below 30
warfarin
How to adjust warfarin, INR below 2 or above 3
below 2 increase weekly dose by 10%
Above 3 decrease dose by 10%
Which anticoagulant should be used with new mechanical valve implant
- warfarin, vitamin K antagonist, Proven to reduce risk of valve thrombosis and systemic embolism (monitor INR)
Treatment for pernicious anemia
Pernicious anemia is a type of vitamin B12 deficiency caused by autoimmune destruction of gastric parietal cells or intrinsic factor (IF) antibodies, which leads to malabsorption of B12 — not dietary deficiency
Treat with vitamin B12 replacement
Which common over counter meds can interfere with absorption of ferrous sulfate
Calcium
Difference between linear and nonlinear dose responses
- Linear Dose-Response in Anticoagulation
Warfarin (Coumadin):
Generally exhibits alinear dose-responsewithin a narrow therapeutic window — small changes in dose can cause proportional changes in INR.
However,individual variability,diet (vitamin K intake), anddrug interactionscan affect predictability. - Non-Linear Dose-Response in Anticoagulation
Heparin
Shows a morenon-linear response, Variable bioavailability. requiresaPTT monitoringto guide dosing.
