A better hope for irregular hearts- Dabigatran

2 days ago  the FDA approved the first new anticoagulant in fifty years, dabigatran  for stroke prevention in patients with non-valvular atrial fibrillation. Available in 75 & 150 mg to be taken twice daily. Dabigatran showed a better side effect profile compared to warfarin in the recently published  RE-LY trial in NEJM. This was a non inferiority trial with 18000 patients. Half received Dabigatran and half..coumadin. Primary outcome was stroke. Compared with Coumadin (warfarin), patients on Dabigatran had a 9% lesser incidence of stroke, and the risk of major bleeding each year was 2.71% with dabi ..and 3.36% per year with warfarin.The risk of hemorrhagic stroke also decreased significantly. These results has pushed FDA to approve this on the market. 


On top of all these benefits.....the one advantage that stands out...is the there is NO NEED TO CHECK BLOOD LEVELS. This is a great news for patients taking warfarin....but may be a bad news for the warfarin clinics!
What is the downside of Dabigatran?  The common side effect is GI intolerance. This was not a major issue in the trial. Second..it is expected to be 7-8 times costlier than warfarin (roughly around $6 -$9 / day). But given the amount spent on blood checks, clinic visits, lost work days, money spent on patients travelling to the clinics..........plus the reduction in complications.....Dabigatran might still prove to be a cost effective medication. Well...who knows........our clever Insurance companies might think differently.     But another important group of concerns are...that there is no antidote in case of a major bleeding ( but due to short half life..stopping the drug could be adequate). Also when to stop before surgeries..and when to restart? How to monitor if needed? Well ...the most reliable means of montoring seems to be activated partial thromboplastin time(aPTT) and Thrombin clottin time (TT).


How does it work? It is a prodrug..and is immediately  converted by a serum esterase to dabigatran, a potent, direct, competitive inhibitor of thrombin. It has an absolute bioavailability of 6.5%, 80% of the given dose is excreted by the kidneys, its serum half-life is 12 to 17 hours. It is approved by FDA at a dose of 150 mg bid. Lets wait and see if this would end the story for warfarin. 


Remember....a direct thrombin inhibitor called Ximelagatran was about to be released in Europe for the same indication as Dabigatran...but had to be withdrawn because of hepatotoxicity during its trials. This was not a great problem in the RE-LY trial. But this something to be aware of especially in the first few months of treatment.