Anticogulants Flashcards
MOA of Warfarin
-Inhibit the hepatic synthesis of several clotting factors, including factor X.
-Inhibits vitamin K-dependent synthesis of clotting factors
Absorption and Distribution of Warfarin
rapidly and completely absorbed orally
highly bound to plasma protein.
Warfarin in pregnancy?
Big No. crosses the placenta and can cause hemorrhagic disorders in the fetus and serious birth defects
Oral factor Xa inhibitors, rivaroxaban, apixaban, have a boxed warning indicating?
premature discontinuation of anticoagulants may lead to thrombotic events
Can warfarin cause skin rash?
Although rare, allergic reactions do occur with warfarin, characterized by symmetrical, maculopapular, erythematous lesions
Is warfarin considered the first choice for DVT or PE?
guidelines recommend apixaban, dabigatran, edoxaban, or rivaroxaban over warfarin as treatment-phase (first 3 months) anticoagulant therapy for DVT of the leg or PE
Normal INR - not on warfarin
0.8-1.1
Warfarin INR goal
2-3
When should INR goal 2.5-3.5?
mechanical valves and high risk
Protocol for warfarin stop/start when having a procedure
Patients who are having surgery should stop warfarin 5 or more days before elective surgery and resume within 24 hours after surgery - unless low bleeding risk
Warfarin Contraindications
Pregnancy, recent surgery, severe hypertension.
MOA of Heparin
Enhances the activity of antithrombin III, inhibiting clotting factors.
MOA of LMWH - enoxaparin (lovenox)
LMWH enoxaparin (Lovenox) potentiates the activity of antithrombin III and inactivates factors Xa and IIa (thrombin)
Difference in distribution between heparin and LMWH
heparin is distributed in plasma and extensively protein bound. The LMWHs are distributed in plasma and have limited or no protein binding
LMWHs are contraindicated in?
contraindicated for patients with allergies to pork, sulfites, or benzyl alcohol; for patients with uncontrolled bleeding; and in patients who have antiplatelet antibodies
Can LMWH be used in pregnancy
yes first-line drug for women who require antithrombotic therapy during pregnancy
is heparin and LMWH absorbed in GI tract?
no - must be given IV or Sq
Heparins are contraindicated in which disease states
advanced hepatic or renal disease.
Unfractionated heparin use in pregnancy?
risk must outweigh benefit
When will thrombocytopenia occur if HIT is going to happen. When should heparin be d/c’d
Early thrombocytopenia occurs 2 to 3 days after initiating therapy, and a delayed form occurs 7 to 12 days after initiation. If the platelet count falls below 100,000/mm3, the heparin should be discontinued.
How many hours before surgery should IV heparin be stopped? SQ?
4-6 hours IV
SQ - 24 hours
MOA of dabigatran
a direct thrombin inhibitor. Thrombin is required for the conversion of fibrinogen to fibrin in the clotting cascade, thus dabigatran’s inhibition of thrombin prevents thrombi from forming
reversal agent for dabigatran if excessive bleeding occurs is
idarucizumab (Praxbind)
Dabigatran has a boxed warning concerning?
increasing risk of thrombotic events upon discontinuation
Angioedema and thrombocytopenia have been reported with which oral anticog?
Dabigatran
2021 ACCP guidelines recommend apixaban, dabigatran, edoxaban, or rivaroxaban over warfarin as treatment-phase, how long?
3 months
patients with AF, the ACCP recommends against antiplatelet therapy alone. For patients with persistent or paroxysmal AF at high risk for stroke, which drugs are recommended?
apixaban, edoxaban, or dabigatran , warfarin 2-3
MOA apixaban(eliquis), Xerelto
Oral direct factor Xa inhibitors selectively inactivate circulating Xa
What is the reversal for eliquis?
there isnt one!
MOA of Plavix (clopidegrel)
Reduce platelet aggregation by inhibiting the ADP pathway of platelets.
MOA Ticagrelor (Brilinta)
reversibly interacts with the platelet P2Y12 ADP receptor to prevent platelet activation.
Is clopidegrel a prodrug?
yep, converts in the liver to active
clopidogrel is not recommended for patients with
severe hepatic disease
ACCP guidelines recommend the combination of aspirin and extended-release __________over aspirin alone be used as preventive therapy for TIA or stroke
dipyridamole or clopidogrel
Clopidogrel should not be taken with _____ because it decreases its effectiveness
proton pump inhibitors (PPIs), such as OTC omeprazole (Prilosec OTC)
MOA of aspirin
It inhibits the production of prostaglandins but inhibits cyclooxygenase (COX), reducing thromboxane A2 production.
What syndrome has been associated in children with aspirin use
Reye Syndrome
Should you take aspirin and NSAIDs together
no no no
What can aspirin do to GI?
cause gastric erosion
Liver function and aspirin relatoinship
use cautiously in hepatic impairment
Signs of aspirin toxicity
In addition to tinnitus, indications of aspirin toxicity are headache, hyperventilation, agitation, mental confusion, lethargy, diarrhea, and sweating.
is aspirin antiplatelt or anticoag?
antiplatelet
Should you stop low dose aspirin before surgery?
No
How far in advance should you stop plavix before surgery
5 days
