Factor Xa inhibitors - the XaBans
It’s just another “me too” drug trying to shoehorn its way into the massive warfarin-replacement market - Ryan Radecki
image by: Julie Dalcourt
HWN Suggests
The New Anticoagulants
The “xabans” are newly available oral agents; both rivaroxaban and apixaban have been approved by the FDA since 2010. Because their onset of action is rapid (peaks in 2-4 hours), parenteral bridging is often unnecessary. While anticoagulant effect is predictable and monitoring of anticoagulation is not required, a special assay is available if it becomes necessary to monitor the activity of the agent.
Rivaroxaban is approved for surgical DVT prophylaxis, stroke prevention in nonvalvular atrial fibrillation and treatment of DVT and PE. To date, apixaban is only approved for stroke prevention in valvular atrial fibrillation.
Resources
Take me to the Rivaroxaban – Outpatient Treatment of VTE
It is certainly reasonable to discuss outpatient treatment with rivaroxaban (or warfarin) for appropriate low-risk emergency department patients with newly diagnosed VTE, but the discussion should include the degree of uncertainty associated with non-randomized, observational studies.
DOACs Part 1: Use and Misuse
The first thing to know about DOAC dosing is that dosages are different for venous thromboembolism than for atrial fibrillation. Dosing for venous thromboembolism is fixed as opposed to atrial fibrillation where it is adjusted based on renal function, weight and age. Apixiban 10mg po bid for 1 week followed by 5mg po bid or Rivaroxiban 15mg po bid for 3 weeks followed by 20mg once daily.
Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation
Treatment with factor Xa inhibitors significantly reduced the number of strokes and systemic embolic events compared with warfarin in people with AF. The absolute effect of factor Xa inhibitors compared with warfarin treatment was, however, rather small. Factor Xa inhibitors also reduced the number of ICHs, all‐cause deaths and major bleedings compared with warfarin, although the evidence for a reduction in the latter is less robust.
How Does Aspirin Compare with Factor Xa Inhibitors for VTE Prophylaxis?
We found that in our study population, aspirin was as effective as factor Xa inhibitors in preventing VTE following TJA. Some patients may need the more-potent drug, however, due to their comorbid conditions. More studies are needed to further clarify this issue.
Safety of PE Treatment with Rivaroxaban
Can low-risk PE patients be safely treated by initiating a DOAC in the ED and then discharging the patient to outpatient follow-up? This study provides further support towards the momentum that is already headed in that direction.
The role of factor Xa inhibitors in venous thromboembolism treatment
Factor Xa inhibitors are small molecules that selectively and reversibly bind to the active site of activated factor X (Xa), which blocks the interaction with its substrate in a rapid and competitive fashion, therefore inhibiting the final effects of thrombin generation. They inhibit both free factor Xa in solution and within a clot, and have no direct effect on platelet aggregation.
Tiny Tip: Banning Factor Xa – How to remember NOACs
Here is the tip: Look for the suffix -xaban in the Xa inhibitors in the GENERIC name of the med.
What are factor Xa inhibitors used for?
Factor Xa is a serine protease which cleaves prothrombin to generate thrombin and lies at the crossroads of the extrinsic and intrinsic coagulation pathway. Only a small amount of factor Xa is needed to generate many molecules of thrombin.
Xabans as Direct Factor X a Inhibitors
Advantages of orally administered direct Xa inhibitors lie in the fact that they have a rapid onset and offset of action which reduces need for “bridging” with a parenteral anticoagulant, that they don’t require frequent monitoring or re-dosing whilst having few strong drug interactions and no food interactions, leading to greater convenience by patients and doctors and that they have a lower risk of intra cranial bleeding in trials
The New Anticoagulants
Rivaroxaban is approved for surgical DVT prophylaxis, stroke prevention in nonvalvular atrial fibrillation and treatment of DVT and PE. To date, apixaban is only approved for stroke prevention in valvular atrial fibrillation.
Andexxa
Andexxa is the first and only specific reversal agent for apixaban or rivaroxaban treated patients with life-threatening or uncontrolled bleeding
Arixtra (Fondaparinux)
ARIXTRA (fondaparinux sodium injection, USP) is a sterile solution containing fondaparinux sodium. It is a synthetic and specific inhibitor of activated Factor X (Xa).
Eliquis (ApiXaBAN)
ELIQUIS (apixaban) is a prescription medicine used to reduce the risk of stroke and blood clots in people who have atrial fibrillation (AFib), a type of irregular heartbeat, not caused by a heart valve problem.
Savaysa (EdoXaBAN}
SAVAYSA is a prescription medicine used to reduce the risk of stroke and blood clots in people who have atrial fibrillation (AFib) not caused by a heart valve problem. Based on how well your kidneys work, SAVAYSA may not be a treatment option for you. Your doctor should check your kidney function before starting treatment.
Xarelto (RiveroXaBAN}
XARELTO® is a prescription anticoagulant, or blood-thinning medication, proven to: •reduce the risk of stroke in people with Atrial Fibrillation (AFib), an irregular heartbeat, not caused by a heart valve problem •treat and help prevent deep vein thrombosis (DVT) and pulmonary embolism (PE), blood clots in deep veins (such as the legs) and in the lungs •reduce the risk of blood clots following hip or knee replacement surgery.
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