Bayer and Johnson & Johnson’s Janssen Pharmaceutical’s blood-thinning drug, Xarelto, has been touted as “a latest generation blood thinner” (xarelto-us.com) and has become the most prescribed blood-thinner in its class, with over 21 million prescription in the US. It works to stop blood clots from forming even before they start.
However, the drug also has a number of harsh and life-threatening side effects, resulting in a number of lawsuits against Bayer.
Xarelto is an anticoagulant and is marketed as a drug to prevent blood clots and reduce the risk of stroke, particularly in patients who have undergone knee or total hip replacement surgery. While those reasons are why the Federal Drug Administration (FDA) first approved the drug, it is now prescribed for many different issues, which include:
- Patients suffering from atrial fibrillation, which occurs when the heart does not beat in the way it should.
- Patients with deep vein thrombosis or pulmonary embolisms (blood clots in a person’s legs or lungs, respectively).
How it Works
Xarelto, also known by its scientific name rivaroxaban, works to stop blood clots from forming in blood vessels. It binds to a substance called Factor Xa to stop the formation of thrombin, an enzyme in blood plasma that causes clotting. Thrombin turns fibrinogen (an essential protein for the formation of blood clots) into fibrin, which impedes blood flow.
Xarelto was looked at as an easier-to-manage substitution for warfarin. Warfarin was developed in the 1950s to aid patients with atrial fibrillation and prevent strokes. However, taking the drug requires at least bi-weekly blood tests and careful monitoring.
Unlike other blood-thinning predecessors, it does not require doctors to prescribe specific doses— it can be prescribed in a once-a-day standard dose. Many patients are able to maintain the same dosage throughout the drug’s regimen. Xarelto offers patients as easier way to manage this medication, as it does not require regular blood monitoring and has no effect on a patient’s diet. Past blood thinners could affect a patient’s vitamin K levels, causing them to avoid foods rich in vitamin K, like leafy greens.
Xarelto’s popularity has nothing do with this class of drug being safer than the alternative warfarin. In fact, Xarelto offers no antidote in case of uncontrolled bleeding or overdose. Recently the FDA rejected an application for a drug to solve this problem, citing a need for more information.
Black box warnings
The FDA has issued black box warnings twice for Xarelto. Black box warnings are the strongest the FDA can impose on a drug and tells patients and doctors that the medication holds serious and life-threatening risks.
The first black box warning was imposed in August 2013, wherein the warning stated a higher risk for blood clots, deep vein thrombosis and epidural/spinal hematoma in parties who quit taking the drug prior to it running its course.
In January 2014, just five months later, the FDA returned its attention to Xarelto with a “warning/precaution” about the risk of bleeding associated with the drug. The recommendation for treating the bleeding requires blood transfusions. Unlike other anticoagulants, Xarelto offers no antidote or way to reverse its effects. Other blood thinning medications can be reversed by giving a patient vitamin K or protamine sulfate to reverse the anticoagulant properties of the blood thinner.
An additional black box warning was issued by the FDA in March 2014. This time, it warned patients that discontinuing the medication prematurely could result in blood clots and strokes. It also warned that people who haven’t fully flushed the drug out of their system and then undergo spinal procedures or spinal anesthesia are in danger of a spinal bleeds or spinal/epidural hematomas. This spinal bleeding can lead to permanent paralysis.
In December 2014, the FDA put another warning on Xarelto, issuing an adverse reaction report. It advised that Xarelto could be the cause of low blood platelet counts, resulting in internal bleeding since platelets are integral to forming blood clots.
That same month, the FDA compiled a list of several drugs that could cause major damage when taken in conjunction with Xarelto.
Itraconazole – Sporanox and Onmel
lopinavir – Kaletra
Ritonavir – Norvir
Indinavir – Crixivan
Conivaptan – Vaprisol
Carbamazepine – Tegretol, Tegretol-XR, Equetro, Carbatrol, Epitol, and Teril
Phenytoin – Dilantin
Rifampin – Rifater, Rifamate, Rimactane, and Rifadin
St. John’s wort – Hypericum Perforatum
Other drugs can increase the risk of bleeding while taking Xarelto, including NSAIDs like ibuprofen and Advil and SSRIs like Zoloft and Prozac.