Coumadin has had a virtual monopoly as an oral anticoagulant since it was first used in 1940 at Wisconsin General Hospital. Discovered accidentally when scientists investigated hemorrhaging of livestock who ate spoiled sweet clover when grazing, it took a decade to isolate dicoumarol and use it in the clinic.
Initially showing success in preventing blood clots in heart attack patients who were recuperating with prolonged bed-rest, it was used in a multiplicity of settings to reduce blood clots and today is most widely used today for stroke prevention in the arrhythmia atrial fibrillation. This monopoly is about to end.
The NOAC group of medication (NOvel AntiCoagulants) are about to displaced Coumadin use due to their ease of use, equivalency, and possible superiority. Pradaxa, Xarelto, & Eliquis are the three major brands of these NOAC medications, and every month there is another publication in the scientific medical literature touting their use and benefits.
In atrial fibrillation, the NOACS are equal to, if not superior to Coumadin for prevention of stroke. Their side effect profiles appear similar or better than Coumadin and they do not require special blood testing, the vaunted PROTIME, to monitor effects.
Beyond fibrillation, Xarelto has been approved for treating blood clots in the legs and lungs, and Eliquis appears that it will be approved soon (Pradaxa is not approved for this condition). Additional indications are being investigated, including use in Mechanical Heart Valves, but that data remains uncertain and will await final proof of effectiveness before it displaces Coumadin as the drug of choice.
There are four hold-ups in the transition from Coumadin to NOACs and they are:
1. Delineation of specific and definitive indications conditions that can benefit from NOACS (Atrial Fibrillation and Blood Clots are proven; Mechanical Hearat Valves and Heart Clots are unproven at this time)
2. Lack of antidote to treat overdose. Although this would seem to be a big ‘hold up’ the clinical evidence suggests that stopping/holding the NOAC medication in most instances results in acceptable clinical outcomes in patients with bleeding issues or trauma, and in exceptional cases that require it, there are some novel IV substances that may help reverse their blood-thinning properties.
3. Cost….as the medications are approximately $10 per pill (cash), while Coumadin is only pennies
4. Lack of extensive data to match Coumadin. As Coumadin has been around for 70+ years, it is difficult for these newer agents to match the data and clinical experience physicians have with these medications, but well-designed studies are being done on tens-of-thousands of patients to attempt to get data that is statistically strong and very reassuring.
So, patients with fibrillation that have varying Protimes (blood test results) or those who have difficulty getting their blood tested, will want to strongly consider the NOAC medications and it appears that without some profoundly negative studies on these medications, they are poised to end the era dominated by Coumadin.