Anticoagulant Flashcards
What is required for successful clotting?
Platelets and coagulation factors
What are the 3 major groups of drugs to tx thromboembolic disorders?
anticoagulants, antiplatelet, and thrombolytics
What is the primary use of anticoagulants?
prevention of thrombosis in veins and the atria of the heart
What is the primary use of antiplatelets?
prevent thrombosis in the arteries
Which class is the only one that breaks up clots?
Thrombolytics
Which anticoagulant affects the extrinsic pathway (Tissue injury) of the coagulation cascade?
Warfarin
MOA of Warfarin (Coumadin)?
- inhibits the synthesis of clotting factors (VII, IX, X, and prothrombin)
- Vitamin K antagonist
Warfarin uses?
- long-term prophylaxis of thrombosis
- heart valve replacement
What labs should we monitor with warfarin?
INR and PT
Adverse effects of warfarin (coumadin)?
hemorrhage
What is the reversal agent for hemorrhage when taking coumadin?
Vitamin K
Warfarin is contraindicated in?
-pregnancy d/t fetal hemorrhage and teratogenesis
D/t Warfarin’s delayed onset which drug is used as a bridge?
Lovenox
Who should we be cautious about when taking Warfarin?
pt’s w/ GI ulcers, hemophilia, and any bleeding disorder
Patient education for Warfarin?
keep a log, f/u with testing, avoid venous stasis, dosage, take at the same time everyday, multiple drug interactions, diet restrictions, reversal agent, use soft bristle toothbrush, electric razor, apply extra pressure to wounds, minimize use of concurrent anticoagulants or antiplatelet.
What does INR measure?
The time it takes for the blood to clot
What does it mean if a patient’s INR is high?
They are at risk for bleeding
What does it mean if a patient’s INR is low?
They are at risk for clots
What are signs of bleeding?
epistaxis, easy bruising, sudden severe HA, bleeding gums, melena, vomiting blood, ↑ HR and ↓ BP, hematuria
Warfarin or heparin is not for patient’s with?
active bleeding (ulcers, wounds), surgery (eye, spinal, brain), renal or liver failure
What class of anticoagulant is heparin?
Indirect thrombin inhibitor; Inactivates factor Xa and thrombin
Routes of heparin administration?
IV or subQ. Avoid the IM route.
What is the preferred anticoagulant during pregnancy?
Heparin
Adverse effects of heparin?
hemorrhage, HIT, hypersensitivity rxns
Heparin contraindications?
low platelets, surgeries, active bleeding
Antidote for heparin?
Protamine sulfate
Which labs should we monitor when administering heparin?
aPTT (only drawn if someone is on a heparin drip) and Anti-factor Xa heparin assay
Pre-administration: BP, HR, RBC count, platelets, HCT
What is the half life of heparin?
1.5hrs
How is Dabigatran etexilate a prodrug?
When it is metabolized it undergoes rapid conversion to active dabigatran, a reversible, direct thrombin inhibitor
Adverse effects of Lovenox?
bleeding but much less than heparin; ITP
Which pathway of the coagulation cascade does heparin affect?
Intrinsic (blood vessel injury)
What is the difference between PTT and aPTT?
Measure the same thing but aPTT has an activator added to speed up the clotting time
Lovenox uses?
prevention and tx of DVTs
Which anticoagulant works faster?
Heparin
What is the therapeutic range for INR with warfarin?
2-3
Do you need frequent blood tests when taking Lovenox?
No
Route of administration for Lovenox?
SubQ, dosage based on body weight
Which medications are direct thrombin inhibitors?
Dabigatran etexilate (Pradaxa, Pradax) and Argatroban
Pradaxa MOA?
Oral prodrug that undergoes rapid conversion dabigatran, a reversible, direct thrombin inhibitor
Pradaxa uses?
A fib, DVT/PE, knee or hip replacement
Should Pradaxa be taken with our without food?
Either
5 major advantages of Pradaxa?
rapid onset, no need to monitor anticoagulation, few drug food interactions, lower risk of major bleeding, and same dose can be used for all patients, regardless of age or weight.
Disadvantages of Pradaxa?
No specific antidote, limited time on the market, more GI disturbances
Uses of argatroban?
prophylaxis and tx of thrombosis in the patients with HIT
Argatroban route?
IV
What is the half life of Argatroban?
~45min
What labs should be monitored with administration of Argatroban?
therapeutic levels of aPTT
MOA of direct factor Xa inhibitors?
inhibit thrombin production by inhibiting factor Xa
Prototypes for direct factor Xa inhibitors?
Rivaroxaban (Xarelto) and Apixaban (Eliquis)
Pharmacokinetics of Direct factor Xa inhibitors?
highly protein bound, partial metabolism by the liver, excreted in urine and feces.
Contraindications for direct factor Xa inhibitors?
pregnancy
T/F. Xarelto has the same advantages and disadvantages of Pradaxa.
True
Uses for Direct factor Xa inhibitors?
DVT prophylaxis including A fib and hip or knee replacement surgery.
MOA of Lovenox?
low molecular weight (LMW) heparin that inhibits factor Xa
Which anticoagulant has CRANKY drug interactions?
Warfarin
Precautions for Direct Xa inhibitors?
patients with renal/liver impairment
