Xarelto (rivaroxaban), an anti-clotting medication, has been approved by the FDA for patients with non-valvular atrial fibrillation to reduce stroke risk. Xarelto, a Factor Xa inhibitor, acts at a crucial point in the blood-clotting process and stops the formation of blood clots. Its principal advantage over other anti-clotting medications (anticoagulants) is that it does not need such close monitoring or dosage adjustments.

Janssen Pharmaceuticals Inc. has the rights to market rivaroxaban in the USA while Bayer Healthcare holds the rights to market it elsewhere in the world. Janssen belongs to Johnson & Johnson.

Atrial fibrillation, one of the most common kinds of abnormal heart rhythm, affects over 2 million people in the USA. The human heart has two upper chambers (atria) and two lower chambers (ventricles). The atria consist of a right and left atrium, and the ventricles consist of the left and right ventricles. If the atria contract to0 quickly or irregularly, the individual has atrial fibrillation. It is caused by a disorder in the electrical system of the heart. Arrhythmia means an irregular heartbeat.

Patients with atrial fibrillation have a higher risk of blood clots forming in the atria. The clot can become dislodged, make its way to the bloodstream and end up in the brain, where it can cause a stroke. Strokes can result in brain damage, and serious behavioral and physical problems, and even death.

Atrial fibrillation patients have a five times higher risk of developing a stroke compared to other people. According to the NIH (National Institutes of Health), approximately one third of patients with atrial fibrillation (AT) have a stroke.

If a person has non-valvular atrial fibrillation, it means they do not have serious problems in their heart valves.

Director of the Division of Cardiovascular and Renal Products in the FDA’s Center for Drug Evaluation and Research, Norman Stockbridge, M.D., Ph.D., said:

“Atrial fibrillation can lead to the formation of blood clots, which can travel to the brain, blocking blood flow and causing a disabling stroke. This approval gives doctors and patients another treatment option for a condition that must be managed carefully.”

When a stroke occurs, the blood flow to a part of the brain is blocked. If brain cells are subsequently damaged or destroyed, other parts of the body can be affected. The patient can experience numbness in the legs, arms or face, they may have problems speaking or understanding what people say, there may be vision problems, difficulties with coordination, incontinence, mobility, etc.

The FDA assessed a clinical trial involving over 14,000 patients. The study compared Xarelto against warfarin, another anticoagulant. Xarelto was found to be just as effective as warfarin in preventing stroke. However, with warfarin doctors have to regularly measure its levels in the patient’s bloodstream. This is not the case with Xarelto. On the other hand, warfarin is much cheaper than Xarelto.

Atrial fibrillation patients should take Xarelto once a day during their evening meal so that it can be totally absorbed.

Xarelto, like other anticoagulants, may cause bleeding that can (rarely) result in death. The most common adverse event reported by patients on Xarelto during the trial was bleeding. Risk of bleeding was found to be similar to that of warfarin. Xarelto caused more bleeding in the stomach and less in the brain.

Discontinuing the drug without checking with a doctor can raise the risk of stroke. In a boxed warning, patients and doctors are informed about this.

When patients or caregivers pick up their Xarelto prescription they will be given a Medication guide; this is an FDA-requirement. The guide explains the risks as well as possible adverse events.

In July this year Xarelto was approved by the FDA for use after knee or hip replacement surgery to reduce the risk of blood clots, DVT (deep vein thrombosis), and pulmonary embolism.

Rivaroxaban’s molecular formula is C19H18ClN3O5S. It is well absorbed in the gut. Maximum factor Xa inhibition occurs four hours after taking it, and its effects last between 8 to 12 hours. However, factor Xa activity is not fully restored for 24 hours, making a once-daily dosing possible.

Written by Christian Nordqvist