Wednesday, December 22, 2010

Another nail in the coffin for warfarin --- Rivaroxaban

The oral factor Xa inhibitor , RIVAROXABAN is posing more threat to the existence of warfarin for management of symptomatic deep venous thrombosis and foe stroke prevention in patients with non-valvular Afib. It is a oral tablet and has excellent bioavailability...has a structure somewhat similar to Linezolid.....and has predictable anticoagulant effect across wide variations in age, weight and gender.This drug has been in use in Canada and UK since last year for DVT prophylaxis following hip and knee it was shown to be non inferior to enoxaparin, for those indications(RECORD trials)
Rats In Peace
The latest trial on Rivaroxaban ,presented at the European Cardiology Congress ........and published in NEJM Dec 2010 is the EINSTEIN-DVT study. This is a non inferiority study involving 2449 pts with DVT randomizing them to either 15mg twice daily for 3 weeks, followed by 20mg daily of rivaroxaban Vs sc enoxaparin followed by warfarin for upto 12 months. The primary efficacy outcome was the first symptomatic VTE event, which occurred in 2.1% of those on rivaroxaban (n=1731) compared with 3% of those on usual care (n=1718), with a hazard ratio of 0.68 (95% CI 0.44-1.04).The two regimens had comparable safety profiles, with the principal safety outcome—a composite of major and nonmajor clinically relevant bleeding events—being 8.1% in both treatment groups (p=0.77). 

Its probably time for a change in the way patients are anticoagulated! and warfarin has managed to hold the fort for more than 50 years. With these new agents(rivaroxaban & dabigatran) it will be easier for patients and no monitoring is needed. 
But few questions still linger.......Can we reverse the bleeding due to rivaroxaban? when do we stop and restart for any surgical procedures? what are its interactions with other commonly used drugs? .....Im sure FDA will be looking into these facts before giving the final nod.