Master Factor Xa Inhibitors with Picmonic for Medicine

Factor X is an important convergence of the intrinsice and extrinsic coagulation cascade pathways. Activation of factor X to Xa causes downstream thrombogenic effects. Inhibiting this factor will prevent downstreem thrombogenesis.

Direct factor Xa inhibitors are recognizable by their suffix "-xaban". The "-Xa-" stands for factor Xa and the "-ban" stands for inhibition.

Apixaban (brand name Eliquis) is a commonly prescribed factor Xa inhibitor. Observational studies show that apixaban has less major bleeding events than rivaroxaban. Apixaban is administered PO with a plasma half‐life of 8-15 hours.

Rivaroxaban (brand name Xarelto) is another commonly prescribed Xa inhibitor. Rivaroxaban is administered via oral with a plasma half‐life of 8-15 hours.

Pulmonary embolism (PE) is a sudden blockage of pulmonary arteries. About 10% of patients die in the first hour and 30% die subsequently from recurrent embolism. Direct factor Xa inhibitors are indicated for treatment and secondary prophylaxis of PE.

Direct Xa inhibitors are used to prevent stroke in non-valvular atrial fibrillation patients. The irregular rhythm of atrial fibrillation causes blood to pool in atria and has a chance of forming clots. These blood clots can dislodge and travel to the brain causing a stroke. Direct factor Xa inhibitors or vitamin K antagonists (e.g. warfarin) are currently indicated in these patients.

Deep vein thrombosis is a condition that clot forms in the deep veins, especially the legs. This clot can dislodge and travel to the lungs, causing a life-threatening pulmonary embolism. Direct factor Xa inhibitors are indicated for treatment and secondary prophylaxis of DVTs.

The main side effect of direct factor Xa inhibitors is bleeding. If a patient develops major bleeding, andexanet alfa can be used as an antidote to reverse the anticoagulant activity of the direct Xa inhibitor. It acts as a decoy to sequester direct factor Xa inhibitors.