A patient wonders: They have atrial fibrillation and take Coumadin to prevent strokes. While they had no difficulty, they wonder if they should switch to one of the newer drugs instead of Coumadin.

For 50 years, warfarin (Coumadin) was the only choice for people that needed to take for anticoagulant. Warfarin is rather inexpensive, but it had downsides. Patients are required to have regular blood tests to ensure the dose are correct. The test, called INR, need to fall into a predetermined range. The result within the proper range means the person’s blood is “thin” enough not to clot easily, but not “too thin” to cause a high bleeding risk.

Unfortunately, it’s not so easy to do. Studies show that countless people on warfarin frequently have an INR result out of the desired range. It makes the blood clot prevention ineffective or puts them at risk for significant bleeding. Wrong dosages or missing doses clearly affect the INR. However, even when taken as prescribed, dietary changes and drug interactions can change the INR dramatically.

(Or you can solve this another way: Try Pharmacogenetic testing! Take the mystery out of it all with a simple buccal swab and know exactly what dosages and medications work for you!)

With new anticoagulants, this can all change. These new drugs are known as direct oral anticoagulants (DOACs). The advantages of DOACs; they don’t require regular blood tests, have no food restrictions and have fewer drug interactions. The problem? They cost far more than warfarin.

To switch to DOAC, a patient must have adequate kidney function. That can be determined by a blood test for creatinine and glomerular filtration rate (GFR). People with a very low GRF cannot safely take the new drugs.

So, if a patient is considering switching, this is what they must consider.

Affordability. Make sure the patient can afford DOAC. Does their insurance cover it completely it? Or can the patient get the drug at a substantial discount?

If the insurance only covers Pradaxa and Eliquis, it means the patient has to take the drug faithfully twice a day instead of once a day with warfarin. The other DOACs such as Xarelto and Savaysa are once a day drugs. Missing a dose puts the patient at a risk of a stroke.

The DOACs are short acting drugs, while warfarin protects the patient for 24 hours. If a patient is prone to missing dosages, warfarin may be best.

Staying on warfarin is fine if INR is staying in the desired rang (2.0 to 3.0) at least 70 percent of the time, provided frequent dose adjustments and getting regular blood tests are not a hassle.


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