How Do Factor Xa Inhibitors Work?
Factor Xa inhibitors are a type of anticoagulant (blood thinning drugs) that work by binding selectively and reversibly to the clotting factor Xa. Factor Xa plays a crucial role in the blood clotting mechanism when you get an injury by forming a mesh to prevent loss of blood. However, clots can form within the body and cause blockages in the arteries, veins, and heart causing heart attacks and stroke.
Blood clotting is a complex process that involves several different pathways in the body, which needs different proteins and cells to work together to seal the site of the injury. After an injury, the body sends a signal to the repair mechanism to seal the site of the injury. A set of string-like proteins connects at the site of the injury and traps the blood cells from flowing out. Factor Xa kick-starts this process of blood clotting.
Factor Xa inhibitor can affect factor Xa that is present in both the blood and an existing clot. This makes factor Xa an excellent target for anticoagulation therapy. Factor Xa inhibitor will not show any direct effect on platelet aggregation. The inhibition of clotting factor Xa has been shown to be a potential target for anticoagulation therapy.
Uses of Factor Xa Inhibitors
Xa inhibitors have the following uses:
- Nonvalvular atrial fibrillation (irregular heartbeat caused by excess pressure or stretching of the heart chambers)
- Venous thromboembolism (blood clot that starts in a vein)
- Reduction of recurrent deep vein thrombosis (blood clots in a deep vein, usually in the legs) and pulmonary embolism (blockage in one of the pulmonary arteries in your lungs)
- Prophylaxis following knee or hip replacement surgery
What Are Side Effects of Factor Xa Inhibitors?
Side effects of factor Xa inhibitors may include:
- The therapeutic effect of factor Xa inhibitors is to prevent clot formation, thereby inherently increasing the risk of unwanted bleeding.
- The most serious bleeding event associated with the use of anticoagulants is intracranial hemorrhage (bleeding within the skull).
- The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.
From 
Healthy Resources
https://reference.medscape.com/drugs/factor-xa-inhibitors
NCBI. The role of factor Xa inhibitors in venous thromboembolism treatment
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4321604/
Medscape. FDA Approves First Factor Xa Inhibitor Antidote, Andexxa.
https://www.medscape.com/viewarticle/896182#:~:text=The%20US%20Food%20and%20Drug,bleeding%2C%20Portola%20Pharmaceuticals%20has%20announced.