Coagulation Flashcards
Factor Xa inhibitor examples
Rivaroxaban (Xarelto)
Apixaban (Eliquis)
Endoxaban (Savaysa)
Betrixaban (Bevyxxa)
Warfarin (Coumadin)
Inhibits synthesis
of vitamin K–dependent clotting factors X, IX, VII, and II (prothrombin)
Heparin
Binds with
antithrombin III
Inactivates factors IXa, Xa, XIIa, XIII
Low-molecular-weight heparin (LMWH)
Regular heparin is processed
into smaller molecules
examples of LMWH and action
Enoxaparin (Lovenox), dalteparin (Fragmin)
Inactivates factor Xa
Fondaparinux (Arixta)
Selective inhibitor of
antithrombin III and factor Xa inhibitor
Heparin and LMWH sometimes will be given as a bridge until
warfarin is effective
Warfarin is well absorbed when taken
orally
warfarin is metabolized by and half life
CYP1A2 and 2C9
Half-life of 3 to 4 days
Warfarin precautions and contraindications
Pregnancy category X
Use cautiously in patients with fall risk, dementia, or uncontrolled hypertension
Avoid in hypermetabolic state
Warfarin ADR
Bleeding
Antidote is vitamin K
Allergic reactions
Warfarin Drug Interactions
Bleeding
Antidote is vitamin K
Allergic reactions
Warfarin anticoagulant effect may be decreased by
Oral contraceptives, carbamazepine, etc.
Vitamin K–containing foods
Warfarin clinical use and dosing
Start at 5 mg per day (7.5 mg/day if weight greater than 80 kg)
Warfarin is the drug of choice for
Drug of choice for deep vein thrombosis (DVT) and pulmonary embolism (PE
Consider lower dose of Warfarin if
Older than 75 years
Multiple comorbid conditions
Elevated liver enzymes
Changing thyroid status
Dose of warfarin is to maintain an INR between
2 and 3
Warfarin monitoring
INR daily until in therapeutic range for 2 consecutive days
Then two or three times weekly for 1 to 2 weeks
Then less frequently but at least every 6 weeks
Factor Xa directly inhibits
Factor Xa in the clotting cascade
Factor Xa reduction in
risk of stroke and systemic embolism in nonvalvular atrial fibrillation
Factor Xa is used as prophylaxis of
DVT following knee replacement surgery
Per the American college of clinical pharamcy the treatmen tfor DVT or PE after initial stabilization is
Factor Xa (dibigatron, rivaroxaban, apixaban or endoxaban for 3 months.)
Warfarin is second line
Factor Xa inhibitors and interacting drugs
Betrixaban and P-glycoprotein (P-gp) inhibitors
Apixaban and P-gp or CYP3A4 inhibitors
Rivaroxaban and P-gp/CYP3A4 inducers
Vorapaxar and CYP3A inhibitors
Oral Direct Thrombin Inhibitors example
Dabigatran (Pradaxa)
Dabigatran is the only
oral direct thrombin inhibitor available for clinical use
Dabigatran is an orally administstred
prodrug that is converted in the liver to dabigatran, an active direct thrombin inhibitor that inhibits clot-bound and circulating thrombin
dabigatran half life
12 to 17 hours (normal renal function)
Dabigatran use
prevention and management of VTE, stroke prevention in afib and ischemic heart disease
Dabigatrain contraindications
prosthetic heart values or pregnancy
dabigatrain
no monitoring
dabigatrain monitoring
none
dabigatran before initiation
platelet count, PT, aPTT – after that no routine monitoring
dabigatran SE
GI
ASA MOA and how long to efffects last
binding irreversibly to the enzyme cyclooxygenase in platelets, which inhibits the formation of thromboxane A2, a powerful inducer of platelet aggregation.
**Effects may persist up to a week.
ASA indication
prevention of stroke & MI
Adenosine diphosphate (ADP) receptor blockers – Examples
Ticlopidine & Clopidogrel (examples)
Adenosine diphosphate (ADP) receptor blockers – MOA
irreversibly block the ADP receptors, altering the plasma membrane of platelets.
Glycoprotein IIb/IIIa receptor antagonists
MOA*:
block the glycoprotein IIb/IIIa receptors
Glycoprotein IIb/IIIa receptor antagonists - Indication
prevent thrombi in recent MI, stroke or PCI
With warfarin monitor
intake of Vit K. eg. green leafy vegitables
