The Antidote for Blood Thinners

Andexanet blood thinner antidote may reduce bleeding risk

/ Author:  / Reviewed by: Beth Bolt, RPh

(RxWiki News) Bleeding can be a major concern for patients taking blood thinners. But what if the effects of these drugs could be safely reversed in an emergency situation?

A team of researchers from McMaster University (MU) and St. Joseph's Healthcare in Canada have successfully developed an antidote designed to reverse the effects of the blood thinners apixaban (brand name Eliquis) and rivaroxaban (Xarelto). By quickly reversing the anticoagulant effects of these drugs, this antidote (known as andexanet) could potentially save the lives of patients with bleeding complications, according to these researchers.

"Bleeding complications present the most common risk for patients taking blood thinners," said lead study author Deborah Siegal, MD, a hematologist at St. Joseph's and a clinical scholar at MU, in a press release. "Without an antidote, there is no way to quickly reverse the effects of a blood thinner in emergency situations. The findings of this study are an advance towards resolving major bleeding complications effectively within minutes."

Blood thinners are a group of drugs used to lower the risk of heart attack, stroke, and other serious medical conditions by reducing the formation of blood clots in the veins and arteries. Because blood thinners slow the clotting of blood, unwanted and sometimes dangerous bleeding can occur.

Andexanet is designed to reverse the effects of blood thinners called factor Xa inhibitors, which inhibit the enzymes necessary for coagulation. Andexanet works as a decoy, fooling these drugs into targeting it instead of the body's coagulation enzymes.

For this study, Dr. Siegal and team looked at 24 healthy older adults who were given 5 milligrams (mg) of apixaban daily for four days. Nine other patients were given placebos.

In the patients on apixaban, anti-factor Xa activity was reduced by 94 percent within two to five minutes of receiving andexanet. Of the patients on placebo, anti-factor Xa activity was reduced by 21 percent.

These researchers next looked at 27 older adults who were given 20 mg of rivaroxaban daily for four days. Fourteen other patients were given placebos.

Anti-factor Xa activity decreased by 92 percent after andexanet in the patients on rivaroxaban compared to 18 percent in the patients on placebo.

This study was published Nov. 11 in The New England Journal of Medicine.

Portola Pharmaceuticals, Bayer, Bristol-Meyers Squibb, Johnson & Johnson and Pfizer funded this research. Portola Pharmaceuticals is the maker of andexanet. The other companies listed make blood thinners.

Dr. Siegal and team disclosed no conflicts of interest.

Reviewed by: 
Review Date: 
November 13, 2015
Last Updated:
November 16, 2015