Archive for the ‘INR’ Category

Dabigatran approved!

October 21, 2010

For the first time in nearly 50 years, patients with Atrial Fibrillation (A-Fib) have a new blood thinning option: Dabigatran. The talk is already starting about how this could replace Warfarin (which is really RAT POISON… we’re just given it in doses too small to kill us!)

One can hope, but there is still a lot that we need to learn about the drug. The US Food and Drug Administration has approved it only as a preventive for stroke caused by A-Fib. Will it even work for anything else? The odds are that it will, but it still needs to be tested. How are people with mechanical valves going to react to it? Somebody’s going to have to take a deep breath and test it. Yet another problem is the cost. Dabigatran is estimated to cost $8 to $12 per day; Warfarin has been around so long that the cost is a pittance. But that is just the cost of the drug – with Warfarin, you also get the required monitoring, in the form of the INR Test. Dabigatran doesn’t require monitoring. Does the cost of Warfarin plus the cost of the test plus supplies make its cost roughly equal with Dabigatran?

There’s another major drawback for certain CHDers: Dabigtran is currently not recommended for “patients with the presence of a severe heart-valve disorder.” That sounds like Tricuspid Atresia patients, Hypoplastic Left Heart Syndrome patients, and those with several other defects are out of luck. Perhaps it is not for us because of lack of testing; if that is the case, the recommendation may change in the future.

At the moment, Dabigatran looks like a drug with a limited potential. Hopefully real world experience will change this.

A Replacement for Warfarin?

March 22, 2010

A lot of people dislike Warfarin. Also known by its brand name Coumadin, it is the most prescribed anticoagulant (Blood thinner) in North America. If you can get past the fact that you are taking something that is also used as rat poison, the constant monitoring and dosage adjustments are a pain in the butt. Every six weeks you must have a blood test, and it reacts with nearly everything. Other medications and even your choice of foods can make the drug more or less effective. This requires you to adjust your medication and have another blood test. It’s enough to make you yell!

But there are two new anticoagulants being developed that could replace Warfarin. The first is Dabigatran, which is marketed in Europe as Pradaxa. Dabigatran was approved for use in Europe and Canada in 2008 and is currently being considered here in the United States by the Food and Drug Administration.

Dabigatran has all the appearances of a wonder drug. It has done well in scientific studies: the RE-LY clinical trail shows that it performs better than Warfarin at some dosage levels; the RECOVER study proves that there is no need for the constant monitoring and no food/drug interactions.

If you’re waiting on the other shoe to drop, here it comes: Dabigatran is expensive. Great Britain’s National Health Service pays £4.20 per day for Dabigatran, and about £1 per day for Warfarin.

Ugh. Now that’s a problem.There are several theories that the cost difference can be recouped not only through the savings in monitoring costs, but the costs associated with stroke recovery. The simpler a medical therapy is to use, the more likely someone is to follow the instructions and benefit from it. Warfarin is difficult to maintain, while Dabigatran wouldn’t be. Just take your pill and go about your business.

The other new drug is Betrixaban, which is still being developed. It’s a joint venture between Merck and Co. and Portola, and like Dabigatran requires no monitoring and has almost no interactions. But it is still in Phase 2 testing, a long way from public use. Also, Portola is developing an “off switch”; another drug that can be administered in case of a heavy bleed and deactivate Betrixaban.

The potential market for any company that can develop a Warfarin replacement that has less interaction and less monitoring needs is wide open. Hopefully market forces will not only benefit the companies developing new drugs, but those of us who rely on them.